xref: /titanic_41/usr/src/uts/common/io/mac/mac_sched.c (revision f33c1cdb6d38eb0715f03cf492f31c3d4d395c98)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/types.h>
27 #include <sys/callb.h>
28 #include <sys/sdt.h>
29 #include <sys/strsubr.h>
30 #include <sys/strsun.h>
31 #include <sys/vlan.h>
32 #include <inet/ipsec_impl.h>
33 #include <inet/ip_impl.h>
34 #include <inet/sadb.h>
35 #include <inet/ipsecesp.h>
36 #include <inet/ipsecah.h>
37 #include <inet/ip6.h>
38 
39 #include <sys/mac_impl.h>
40 #include <sys/mac_client_impl.h>
41 #include <sys/mac_client_priv.h>
42 #include <sys/mac_soft_ring.h>
43 #include <sys/mac_flow_impl.h>
44 
45 static mac_tx_cookie_t mac_tx_single_ring_mode(mac_soft_ring_set_t *, mblk_t *,
46     uintptr_t, uint16_t, mblk_t **);
47 static mac_tx_cookie_t mac_tx_serializer_mode(mac_soft_ring_set_t *, mblk_t *,
48     uintptr_t, uint16_t, mblk_t **);
49 static mac_tx_cookie_t mac_tx_fanout_mode(mac_soft_ring_set_t *, mblk_t *,
50     uintptr_t, uint16_t, mblk_t **);
51 static mac_tx_cookie_t mac_tx_bw_mode(mac_soft_ring_set_t *, mblk_t *,
52     uintptr_t, uint16_t, mblk_t **);
53 
54 typedef struct mac_tx_mode_s {
55 	mac_tx_srs_mode_t	mac_tx_mode;
56 	mac_tx_func_t		mac_tx_func;
57 } mac_tx_mode_t;
58 
59 /*
60  * There are five modes of operation on the Tx side. These modes get set
61  * in mac_tx_srs_setup(). Except for the experimental TX_SERIALIZE mode,
62  * none of the other modes are user configurable. They get selected by
63  * the system depending upon whether the link (or flow) has multiple Tx
64  * rings or a bandwidth configured, etc.
65  */
66 mac_tx_mode_t mac_tx_mode_list[] = {
67 	{SRS_TX_DEFAULT,	mac_tx_single_ring_mode},
68 	{SRS_TX_SERIALIZE,	mac_tx_serializer_mode},
69 	{SRS_TX_FANOUT,		mac_tx_fanout_mode},
70 	{SRS_TX_BW,		mac_tx_bw_mode},
71 	{SRS_TX_BW_FANOUT,	mac_tx_bw_mode}
72 };
73 
74 /*
75  * Soft Ring Set (SRS) - The Run time code that deals with
76  * dynamic polling from the hardware, bandwidth enforcement,
77  * fanout etc.
78  *
79  * We try to use H/W classification on NIC and assign traffic for
80  * a MAC address to a particular Rx ring or ring group. There is a
81  * 1-1 mapping between a SRS and a Rx ring. The SRS dynamically
82  * switches the underlying Rx ring between interrupt and
83  * polling mode and enforces any specified B/W control.
84  *
85  * There is always a SRS created and tied to each H/W and S/W rule.
86  * Whenever we create a H/W rule, we always add the the same rule to
87  * S/W classifier and tie a SRS to it.
88  *
89  * In case a B/W control is specified, it is broken into bytes
90  * per ticks and as soon as the quota for a tick is exhausted,
91  * the underlying Rx ring is forced into poll mode for remainder of
92  * the tick. The SRS poll thread only polls for bytes that are
93  * allowed to come in the SRS. We typically let 4x the configured
94  * B/W worth of packets to come in the SRS (to prevent unnecessary
95  * drops due to bursts) but only process the specified amount.
96  *
97  * A MAC client (e.g. a VNIC or aggr) can have 1 or more
98  * Rx rings (and corresponding SRSs) assigned to it. The SRS
99  * in turn can have softrings to do protocol level fanout or
100  * softrings to do S/W based fanout or both. In case the NIC
101  * has no Rx rings, we do S/W classification to respective SRS.
102  * The S/W classification rule is always setup and ready. This
103  * allows the MAC layer to reassign Rx rings whenever needed
104  * but packets still continue to flow via the default path and
105  * getting S/W classified to correct SRS.
106  *
107  * The SRS's are used on both Tx and Rx side. They use the same
108  * data structure but the processing routines have slightly different
109  * semantics due to the fact that Rx side needs to do dynamic
110  * polling etc.
111  *
112  * Dynamic Polling Notes
113  * =====================
114  *
115  * Each Soft ring set is capable of switching its Rx ring between
116  * interrupt and poll mode and actively 'polls' for packets in
117  * poll mode. If the SRS is implementing a B/W limit, it makes
118  * sure that only Max allowed packets are pulled in poll mode
119  * and goes to poll mode as soon as B/W limit is exceeded. As
120  * such, there are no overheads to implement B/W limits.
121  *
122  * In poll mode, its better to keep the pipeline going where the
123  * SRS worker thread keeps processing packets and poll thread
124  * keeps bringing more packets (specially if they get to run
125  * on different CPUs). This also prevents the overheads associated
126  * by excessive signalling (on NUMA machines, this can be
127  * pretty devastating). The exception is latency optimized case
128  * where worker thread does no work and interrupt and poll thread
129  * are allowed to do their own drain.
130  *
131  * We use the following policy to control Dynamic Polling:
132  * 1) We switch to poll mode anytime the processing
133  *    thread causes a backlog to build up in SRS and
134  *    its associated Soft Rings (sr_poll_pkt_cnt > 0).
135  * 2) As long as the backlog stays under the low water
136  *    mark (sr_lowat), we poll the H/W for more packets.
137  * 3) If the backlog (sr_poll_pkt_cnt) exceeds low
138  *    water mark, we stay in poll mode but don't poll
139  *    the H/W for more packets.
140  * 4) Anytime in polling mode, if we poll the H/W for
141  *    packets and find nothing plus we have an existing
142  *    backlog (sr_poll_pkt_cnt > 0), we stay in polling
143  *    mode but don't poll the H/W for packets anymore
144  *    (let the polling thread go to sleep).
145  * 5) Once the backlog is relived (packets are processed)
146  *    we reenable polling (by signalling the poll thread)
147  *    only when the backlog dips below sr_poll_thres.
148  * 6) sr_hiwat is used exclusively when we are not
149  *    polling capable and is used to decide when to
150  *    drop packets so the SRS queue length doesn't grow
151  *    infinitely.
152  *
153  * NOTE: Also see the block level comment on top of mac_soft_ring.c
154  */
155 
156 /*
157  * mac_latency_optimize
158  *
159  * Controls whether the poll thread can process the packets inline
160  * or let the SRS worker thread do the processing. This applies if
161  * the SRS was not being processed. For latency sensitive traffic,
162  * this needs to be true to allow inline processing. For throughput
163  * under load, this should be false.
164  *
165  * This (and other similar) tunable should be rolled into a link
166  * or flow specific workload hint that can be set using dladm
167  * linkprop (instead of multiple such tunables).
168  */
169 boolean_t mac_latency_optimize = B_TRUE;
170 
171 /*
172  * MAC_RX_SRS_ENQUEUE_CHAIN and MAC_TX_SRS_ENQUEUE_CHAIN
173  *
174  * queue a mp or chain in soft ring set and increment the
175  * local count (srs_count) for the SRS and the shared counter
176  * (srs_poll_pkt_cnt - shared between SRS and its soft rings
177  * to track the total unprocessed packets for polling to work
178  * correctly).
179  *
180  * The size (total bytes queued) counters are incremented only
181  * if we are doing B/W control.
182  */
183 #define	MAC_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz) {		\
184 	ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));			\
185 	if ((mac_srs)->srs_last != NULL)				\
186 		(mac_srs)->srs_last->b_next = (head);			\
187 	else								\
188 		(mac_srs)->srs_first = (head);				\
189 	(mac_srs)->srs_last = (tail);					\
190 	(mac_srs)->srs_count += count;					\
191 }
192 
193 #define	MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz) {	\
194 	mac_srs_rx_t	*srs_rx = &(mac_srs)->srs_rx;			\
195 									\
196 	MAC_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz);		\
197 	srs_rx->sr_poll_pkt_cnt += count;				\
198 	ASSERT(srs_rx->sr_poll_pkt_cnt > 0);				\
199 	if ((mac_srs)->srs_type & SRST_BW_CONTROL) {			\
200 		(mac_srs)->srs_size += (sz);				\
201 		mutex_enter(&(mac_srs)->srs_bw->mac_bw_lock);		\
202 		(mac_srs)->srs_bw->mac_bw_sz += (sz);			\
203 		mutex_exit(&(mac_srs)->srs_bw->mac_bw_lock);		\
204 	}								\
205 }
206 
207 #define	MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz) {	\
208 	mac_srs->srs_state |= SRS_ENQUEUED;				\
209 	MAC_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz);		\
210 	if ((mac_srs)->srs_type & SRST_BW_CONTROL) {			\
211 		(mac_srs)->srs_size += (sz);				\
212 		(mac_srs)->srs_bw->mac_bw_sz += (sz);			\
213 	}								\
214 }
215 
216 /*
217  * Turn polling on routines
218  */
219 #define	MAC_SRS_POLLING_ON(mac_srs) {					\
220 	ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));			\
221 	if (((mac_srs)->srs_state &					\
222 	    (SRS_POLLING_CAPAB|SRS_POLLING)) == SRS_POLLING_CAPAB) {	\
223 		(mac_srs)->srs_state |= SRS_POLLING;			\
224 		(void) mac_hwring_disable_intr((mac_ring_handle_t)	\
225 		    (mac_srs)->srs_ring);				\
226 		(mac_srs)->srs_rx.sr_poll_on++;				\
227 	}								\
228 }
229 
230 #define	MAC_SRS_WORKER_POLLING_ON(mac_srs) {				\
231 	ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));			\
232 	if (((mac_srs)->srs_state &					\
233 	    (SRS_POLLING_CAPAB|SRS_WORKER|SRS_POLLING)) == 		\
234 	    (SRS_POLLING_CAPAB|SRS_WORKER)) {				\
235 		(mac_srs)->srs_state |= SRS_POLLING;			\
236 		(void) mac_hwring_disable_intr((mac_ring_handle_t)	\
237 		    (mac_srs)->srs_ring);				\
238 		(mac_srs)->srs_rx.sr_worker_poll_on++;			\
239 	}								\
240 }
241 
242 /*
243  * MAC_SRS_POLL_RING
244  *
245  * Signal the SRS poll thread to poll the underlying H/W ring
246  * provided it wasn't already polling (SRS_GET_PKTS was set).
247  *
248  * Poll thread gets to run only from mac_rx_srs_drain() and only
249  * if the drain was being done by the worker thread.
250  */
251 #define	MAC_SRS_POLL_RING(mac_srs) {					\
252 	mac_srs_rx_t	*srs_rx = &(mac_srs)->srs_rx;			\
253 									\
254 	ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));			\
255 	srs_rx->sr_poll_thr_sig++;					\
256 	if (((mac_srs)->srs_state & 					\
257 	    (SRS_POLLING_CAPAB|SRS_WORKER|SRS_GET_PKTS)) ==		\
258 		(SRS_WORKER|SRS_POLLING_CAPAB)) {			\
259 		(mac_srs)->srs_state |= SRS_GET_PKTS;			\
260 		cv_signal(&(mac_srs)->srs_cv);   			\
261 	} else {							\
262 		srs_rx->sr_poll_thr_busy++;				\
263 	}								\
264 }
265 
266 /*
267  * MAC_SRS_CHECK_BW_CONTROL
268  *
269  * Check to see if next tick has started so we can reset the
270  * SRS_BW_ENFORCED flag and allow more packets to come in the
271  * system.
272  */
273 #define	MAC_SRS_CHECK_BW_CONTROL(mac_srs) {				\
274 	ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));			\
275 	ASSERT(((mac_srs)->srs_type & SRST_TX) ||			\
276 	    MUTEX_HELD(&(mac_srs)->srs_bw->mac_bw_lock));		\
277 	if ((mac_srs)->srs_bw->mac_bw_curr_time != lbolt) {    		\
278 		(mac_srs)->srs_bw->mac_bw_curr_time = lbolt;   		\
279 		(mac_srs)->srs_bw->mac_bw_used = 0;	       		\
280 		if ((mac_srs)->srs_bw->mac_bw_state & SRS_BW_ENFORCED)	\
281 			(mac_srs)->srs_bw->mac_bw_state &= ~SRS_BW_ENFORCED; \
282 	}								\
283 }
284 
285 /*
286  * MAC_SRS_WORKER_WAKEUP
287  *
288  * Wake up the SRS worker thread to process the queue as long as
289  * no one else is processing the queue. If we are optimizing for
290  * latency, we wake up the worker thread immediately or else we
291  * wait mac_srs_worker_wakeup_ticks before worker thread gets
292  * woken up.
293  */
294 int mac_srs_worker_wakeup_ticks = 0;
295 #define	MAC_SRS_WORKER_WAKEUP(mac_srs) {				\
296 	ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));			\
297 	if (!((mac_srs)->srs_state & SRS_PROC) &&			\
298 		(mac_srs)->srs_tid == NULL) {				\
299 		if (((mac_srs)->srs_state & SRS_LATENCY_OPT) ||		\
300 			(mac_srs_worker_wakeup_ticks == 0))		\
301 			cv_signal(&(mac_srs)->srs_async);		\
302 		else							\
303 			(mac_srs)->srs_tid =				\
304 				timeout(mac_srs_fire, (mac_srs),	\
305 					mac_srs_worker_wakeup_ticks);	\
306 	}								\
307 }
308 
309 #define	TX_SINGLE_RING_MODE(mac_srs)				\
310 	((mac_srs)->srs_tx.st_mode == SRS_TX_DEFAULT || 	\
311 	    (mac_srs)->srs_tx.st_mode == SRS_TX_SERIALIZE ||	\
312 	    (mac_srs)->srs_tx.st_mode == SRS_TX_BW)
313 
314 #define	TX_BANDWIDTH_MODE(mac_srs)				\
315 	((mac_srs)->srs_tx.st_mode == SRS_TX_BW ||		\
316 	    (mac_srs)->srs_tx.st_mode == SRS_TX_BW_FANOUT)
317 
318 #define	TX_SRS_TO_SOFT_RING(mac_srs, head, hint) {			\
319 	uint_t hash, indx;						\
320 	hash = HASH_HINT(hint);					\
321 	indx = COMPUTE_INDEX(hash, mac_srs->srs_oth_ring_count);	\
322 	softring = mac_srs->srs_oth_soft_rings[indx];			\
323 	(void) (mac_tx_soft_ring_process(softring, head, 0, NULL));	\
324 }
325 
326 /*
327  * MAC_TX_SRS_BLOCK
328  *
329  * Always called from mac_tx_srs_drain() function. SRS_TX_BLOCKED
330  * will be set only if srs_tx_woken_up is FALSE. If
331  * srs_tx_woken_up is TRUE, it indicates that the wakeup arrived
332  * before we grabbed srs_lock to set SRS_TX_BLOCKED. We need to
333  * attempt to transmit again and not setting SRS_TX_BLOCKED does
334  * that.
335  */
336 #define	MAC_TX_SRS_BLOCK(srs, mp)	{			\
337 	ASSERT(MUTEX_HELD(&(srs)->srs_lock));			\
338 	if ((srs)->srs_tx.st_woken_up) {			\
339 		(srs)->srs_tx.st_woken_up = B_FALSE;		\
340 	} else {						\
341 		ASSERT(!((srs)->srs_state & SRS_TX_BLOCKED));	\
342 		(srs)->srs_state |= SRS_TX_BLOCKED;		\
343 		(srs)->srs_tx.st_blocked_cnt++;			\
344 	}							\
345 }
346 
347 /*
348  * MAC_TX_SRS_TEST_HIWAT
349  *
350  * Called before queueing a packet onto Tx SRS to test and set
351  * SRS_TX_HIWAT if srs_count exceeds srs_tx_hiwat.
352  */
353 #define	MAC_TX_SRS_TEST_HIWAT(srs, mp, tail, cnt, sz, cookie) {		\
354 	boolean_t enqueue = 1;						\
355 									\
356 	if ((srs)->srs_count > (srs)->srs_tx.st_hiwat) {		\
357 		/*							\
358 		 * flow-controlled. Store srs in cookie so that it	\
359 		 * can be returned as mac_tx_cookie_t to client		\
360 		 */							\
361 		(srs)->srs_state |= SRS_TX_HIWAT;			\
362 		cookie = (mac_tx_cookie_t)srs;				\
363 		(srs)->srs_tx.st_hiwat_cnt++;				\
364 		if ((srs)->srs_count > (srs)->srs_tx.st_max_q_cnt) {	\
365 			/* increment freed stats */			\
366 			(srs)->srs_tx.st_drop_count += cnt;		\
367 			/*						\
368 			 * b_prev may be set to the fanout hint		\
369 			 * hence can't use freemsg directly		\
370 			 */						\
371 			mac_pkt_drop(NULL, NULL, mp_chain, B_FALSE);	\
372 			DTRACE_PROBE1(tx_queued_hiwat,			\
373 			    mac_soft_ring_set_t *, srs);		\
374 			enqueue = 0;					\
375 		}							\
376 	}								\
377 	if (enqueue)							\
378 		MAC_TX_SRS_ENQUEUE_CHAIN(srs, mp, tail, cnt, sz);	\
379 }
380 
381 /* Some utility macros */
382 #define	MAC_SRS_BW_LOCK(srs)						\
383 	if (!(srs->srs_type & SRST_TX))					\
384 		mutex_enter(&srs->srs_bw->mac_bw_lock);
385 
386 #define	MAC_SRS_BW_UNLOCK(srs)						\
387 	if (!(srs->srs_type & SRST_TX))					\
388 		mutex_exit(&srs->srs_bw->mac_bw_lock);
389 
390 #define	MAC_TX_SRS_DROP_MESSAGE(srs, mp, cookie) {		\
391 	mac_pkt_drop(NULL, NULL, mp, B_FALSE);			\
392 	/* increment freed stats */				\
393 	mac_srs->srs_tx.st_drop_count++;			\
394 	cookie = (mac_tx_cookie_t)srs;				\
395 }
396 
397 #define	MAC_TX_SET_NO_ENQUEUE(srs, mp_chain, ret_mp, cookie) {		\
398 	mac_srs->srs_state |= SRS_TX_WAKEUP_CLIENT;			\
399 	cookie = (mac_tx_cookie_t)srs;					\
400 	*ret_mp = mp_chain;						\
401 }
402 
403 /*
404  * Drop the rx packet and advance to the next one in the chain.
405  */
406 static void
407 mac_rx_drop_pkt(mac_soft_ring_set_t *srs, mblk_t *mp)
408 {
409 	mac_srs_rx_t	*srs_rx = &srs->srs_rx;
410 
411 	ASSERT(mp->b_next == NULL);
412 	mutex_enter(&srs->srs_lock);
413 	MAC_UPDATE_SRS_COUNT_LOCKED(srs, 1);
414 	MAC_UPDATE_SRS_SIZE_LOCKED(srs, msgdsize(mp));
415 	mutex_exit(&srs->srs_lock);
416 
417 	srs_rx->sr_drop_count++;
418 	freemsg(mp);
419 }
420 
421 /* DATAPATH RUNTIME ROUTINES */
422 
423 /*
424  * mac_srs_fire
425  *
426  * Timer callback routine for waking up the SRS worker thread.
427  */
428 static void
429 mac_srs_fire(void *arg)
430 {
431 	mac_soft_ring_set_t *mac_srs = (mac_soft_ring_set_t *)arg;
432 
433 	mutex_enter(&mac_srs->srs_lock);
434 	if (mac_srs->srs_tid == 0) {
435 		mutex_exit(&mac_srs->srs_lock);
436 		return;
437 	}
438 
439 	mac_srs->srs_tid = 0;
440 	if (!(mac_srs->srs_state & SRS_PROC))
441 		cv_signal(&mac_srs->srs_async);
442 
443 	mutex_exit(&mac_srs->srs_lock);
444 }
445 
446 /*
447  * 'hint' is fanout_hint (type of uint64_t) which is given by the TCP/IP stack,
448  * and it is used on the TX path.
449  */
450 #define	HASH_HINT(hint)	(((hint) << 17) | ((hint) >> 16))
451 
452 /*
453  * hash based on the src address and the port information.
454  */
455 #define	HASH_ADDR(src, ports)					\
456 	(ntohl((src)) ^ ((ports) >> 24) ^ ((ports) >> 16) ^	\
457 	((ports) >> 8) ^ (ports))
458 
459 #define	COMPUTE_INDEX(key, sz)	(key % sz)
460 
461 #define	FANOUT_ENQUEUE_MP(head, tail, cnt, bw_ctl, sz, sz0, mp) {	\
462 	if ((tail) != NULL) {						\
463 		ASSERT((tail)->b_next == NULL);				\
464 		(tail)->b_next = (mp);					\
465 	} else {							\
466 		ASSERT((head) == NULL);					\
467 		(head) = (mp);						\
468 	}								\
469 	(tail) = (mp);							\
470 	(cnt)++;							\
471 	if ((bw_ctl))							\
472 		(sz) += (sz0);						\
473 }
474 
475 #define	MAC_FANOUT_DEFAULT	0
476 #define	MAC_FANOUT_RND_ROBIN	1
477 int mac_fanout_type = MAC_FANOUT_DEFAULT;
478 
479 #define	MAX_SR_TYPES	3
480 /* fanout types for port based hashing */
481 enum pkt_type {
482 	V4_TCP = 0,
483 	V4_UDP,
484 	OTH,
485 	UNDEF
486 };
487 
488 /*
489  * In general we do port based hashing to spread traffic over different
490  * softrings. The below tunable allows to override that behavior. Setting it
491  * to B_TRUE allows to do a fanout based on src ipv6 address. This behavior
492  * is also the applicable to ipv6 packets carrying multiple optional headers
493  * and other uncommon packet types.
494  */
495 boolean_t mac_src_ipv6_fanout = B_FALSE;
496 
497 /*
498  * Pair of local and remote ports in the transport header
499  */
500 #define	PORTS_SIZE 4
501 
502 /*
503  * mac_rx_srs_proto_fanout
504  *
505  * This routine delivers packets destined to an SRS into one of the
506  * protocol soft rings.
507  *
508  * Given a chain of packets we need to split it up into multiple sub chains
509  * destined into TCP, UDP or OTH soft ring. Instead of entering
510  * the soft ring one packet at a time, we want to enter it in the form of a
511  * chain otherwise we get this start/stop behaviour where the worker thread
512  * goes to sleep and then next packets comes in forcing it to wake up etc.
513  */
514 static void
515 mac_rx_srs_proto_fanout(mac_soft_ring_set_t *mac_srs, mblk_t *head)
516 {
517 	struct ether_header		*ehp;
518 	struct ether_vlan_header	*evhp;
519 	uint32_t			sap;
520 	ipha_t				*ipha;
521 	uint8_t				*dstaddr;
522 	size_t				hdrsize;
523 	mblk_t				*mp;
524 	mblk_t				*headmp[MAX_SR_TYPES];
525 	mblk_t				*tailmp[MAX_SR_TYPES];
526 	int				cnt[MAX_SR_TYPES];
527 	size_t				sz[MAX_SR_TYPES];
528 	size_t				sz1;
529 	boolean_t			bw_ctl;
530 	boolean_t			hw_classified;
531 	boolean_t			dls_bypass;
532 	boolean_t			is_ether;
533 	boolean_t			is_unicast;
534 	enum pkt_type			type;
535 	mac_client_impl_t		*mcip = mac_srs->srs_mcip;
536 
537 	is_ether = (mcip->mci_mip->mi_info.mi_nativemedia == DL_ETHER);
538 	bw_ctl = ((mac_srs->srs_type & SRST_BW_CONTROL) != 0);
539 
540 	/*
541 	 * If we don't have a Rx ring, S/W classification would have done
542 	 * its job and its a packet meant for us. If we were polling on
543 	 * the default ring (i.e. there was a ring assigned to this SRS),
544 	 * then we need to make sure that the mac address really belongs
545 	 * to us.
546 	 */
547 	hw_classified = mac_srs->srs_ring != NULL &&
548 	    mac_srs->srs_ring->mr_classify_type == MAC_HW_CLASSIFIER;
549 
550 	/*
551 	 * Special clients (eg. VLAN, non ether, etc) need DLS
552 	 * processing in the Rx path. SRST_DLS_BYPASS will be clear for
553 	 * such SRSs.
554 	 */
555 	dls_bypass = ((mac_srs->srs_type & SRST_DLS_BYPASS) != 0);
556 
557 	bzero(headmp, MAX_SR_TYPES * sizeof (mblk_t *));
558 	bzero(tailmp, MAX_SR_TYPES * sizeof (mblk_t *));
559 	bzero(cnt, MAX_SR_TYPES * sizeof (int));
560 	bzero(sz, MAX_SR_TYPES * sizeof (size_t));
561 
562 	/*
563 	 * We got a chain from SRS that we need to send to the soft rings.
564 	 * Since squeues for TCP & IPv4 sap poll their soft rings (for
565 	 * performance reasons), we need to separate out v4_tcp, v4_udp
566 	 * and the rest goes in other.
567 	 */
568 	while (head != NULL) {
569 		mp = head;
570 		head = head->b_next;
571 		mp->b_next = NULL;
572 
573 		type = OTH;
574 		sz1 = (mp->b_cont == NULL) ? MBLKL(mp) : msgdsize(mp);
575 
576 		if (is_ether) {
577 			/*
578 			 * At this point we can be sure the packet at least
579 			 * has an ether header.
580 			 */
581 			if (sz1 < sizeof (struct ether_header)) {
582 				mac_rx_drop_pkt(mac_srs, mp);
583 				continue;
584 			}
585 			ehp = (struct ether_header *)mp->b_rptr;
586 
587 			/*
588 			 * Determine if this is a VLAN or non-VLAN packet.
589 			 */
590 			if ((sap = ntohs(ehp->ether_type)) == VLAN_TPID) {
591 				evhp = (struct ether_vlan_header *)mp->b_rptr;
592 				sap = ntohs(evhp->ether_type);
593 				hdrsize = sizeof (struct ether_vlan_header);
594 				/*
595 				 * Check if the VID of the packet, if any,
596 				 * belongs to this client.
597 				 */
598 				if (!mac_client_check_flow_vid(mcip,
599 				    VLAN_ID(ntohs(evhp->ether_tci)))) {
600 					mac_rx_drop_pkt(mac_srs, mp);
601 					continue;
602 				}
603 			} else {
604 				hdrsize = sizeof (struct ether_header);
605 			}
606 			is_unicast =
607 			    ((((uint8_t *)&ehp->ether_dhost)[0] & 0x01) == 0);
608 			dstaddr = (uint8_t *)&ehp->ether_dhost;
609 		} else {
610 			mac_header_info_t		mhi;
611 
612 			if (mac_header_info((mac_handle_t)mcip->mci_mip,
613 			    mp, &mhi) != 0) {
614 				mac_rx_drop_pkt(mac_srs, mp);
615 				continue;
616 			}
617 			hdrsize = mhi.mhi_hdrsize;
618 			sap = mhi.mhi_bindsap;
619 			is_unicast = (mhi.mhi_dsttype == MAC_ADDRTYPE_UNICAST);
620 			dstaddr = (uint8_t *)mhi.mhi_daddr;
621 		}
622 
623 		if (!dls_bypass) {
624 			FANOUT_ENQUEUE_MP(headmp[type], tailmp[type],
625 			    cnt[type], bw_ctl, sz[type], sz1, mp);
626 			continue;
627 		}
628 
629 		if (sap == ETHERTYPE_IP) {
630 			/*
631 			 * If we are H/W classified, but we have promisc
632 			 * on, then we need to check for the unicast address.
633 			 */
634 			if (hw_classified && mcip->mci_promisc_list != NULL) {
635 				mac_address_t		*map;
636 
637 				rw_enter(&mcip->mci_rw_lock, RW_READER);
638 				map = mcip->mci_unicast;
639 				if (bcmp(dstaddr, map->ma_addr,
640 				    map->ma_len) == 0)
641 					type = UNDEF;
642 				rw_exit(&mcip->mci_rw_lock);
643 			} else if (is_unicast) {
644 				type = UNDEF;
645 			}
646 		}
647 
648 		/*
649 		 * This needs to become a contract with the driver for
650 		 * the fast path.
651 		 *
652 		 * In the normal case the packet will have at least the L2
653 		 * header and the IP + Transport header in the same mblk.
654 		 * This is usually the case when the NIC driver sends up
655 		 * the packet. This is also true when the stack generates
656 		 * a packet that is looped back and when the stack uses the
657 		 * fastpath mechanism. The normal case is optimized for
658 		 * performance and may bypass DLS. All other cases go through
659 		 * the 'OTH' type path without DLS bypass.
660 		 */
661 
662 		ipha = (ipha_t *)(mp->b_rptr + hdrsize);
663 		if ((type != OTH) && MBLK_RX_FANOUT_SLOWPATH(mp, ipha))
664 			type = OTH;
665 
666 		if (type == OTH) {
667 			FANOUT_ENQUEUE_MP(headmp[type], tailmp[type],
668 			    cnt[type], bw_ctl, sz[type], sz1, mp);
669 			continue;
670 		}
671 
672 		ASSERT(type == UNDEF);
673 		/*
674 		 * We look for at least 4 bytes past the IP header to get
675 		 * the port information. If we get an IP fragment, we don't
676 		 * have the port information, and we use just the protocol
677 		 * information.
678 		 */
679 		switch (ipha->ipha_protocol) {
680 		case IPPROTO_TCP:
681 			type = V4_TCP;
682 			mp->b_rptr += hdrsize;
683 			break;
684 		case IPPROTO_UDP:
685 			type = V4_UDP;
686 			mp->b_rptr += hdrsize;
687 			break;
688 		default:
689 			type = OTH;
690 			break;
691 		}
692 
693 		FANOUT_ENQUEUE_MP(headmp[type], tailmp[type], cnt[type],
694 		    bw_ctl, sz[type], sz1, mp);
695 	}
696 
697 	for (type = V4_TCP; type < UNDEF; type++) {
698 		if (headmp[type] != NULL) {
699 			mac_soft_ring_t			*softring;
700 
701 			ASSERT(tailmp[type]->b_next == NULL);
702 			switch (type) {
703 			case V4_TCP:
704 				softring = mac_srs->srs_tcp_soft_rings[0];
705 				break;
706 			case V4_UDP:
707 				softring = mac_srs->srs_udp_soft_rings[0];
708 				break;
709 			case OTH:
710 				softring = mac_srs->srs_oth_soft_rings[0];
711 			}
712 			mac_rx_soft_ring_process(mcip, softring,
713 			    headmp[type], tailmp[type], cnt[type], sz[type]);
714 		}
715 	}
716 }
717 
718 int	fanout_unalligned = 0;
719 
720 /*
721  * mac_rx_srs_long_fanout
722  *
723  * The fanout routine for IPv6
724  */
725 static int
726 mac_rx_srs_long_fanout(mac_soft_ring_set_t *mac_srs, mblk_t *mp,
727     uint32_t sap, size_t hdrsize, enum pkt_type *type, uint_t *indx)
728 {
729 	ip6_t		*ip6h;
730 	uint8_t		*whereptr;
731 	uint_t		hash;
732 	uint16_t	remlen;
733 	uint8_t		nexthdr;
734 	uint16_t	hdr_len;
735 
736 	if (sap == ETHERTYPE_IPV6) {
737 		boolean_t	modifiable = B_TRUE;
738 
739 		ASSERT(MBLKL(mp) >= hdrsize);
740 
741 		ip6h = (ip6_t *)(mp->b_rptr + hdrsize);
742 		if ((unsigned char *)ip6h == mp->b_wptr) {
743 			/*
744 			 * The first mblk_t only includes the mac header.
745 			 * Note that it is safe to change the mp pointer here,
746 			 * as the subsequent operation does not assume mp
747 			 * points to the start of the mac header.
748 			 */
749 			mp = mp->b_cont;
750 
751 			/*
752 			 * Make sure ip6h holds the full ip6_t structure.
753 			 */
754 			if (mp == NULL)
755 				return (-1);
756 
757 			if (MBLKL(mp) < IPV6_HDR_LEN) {
758 				modifiable = (DB_REF(mp) == 1);
759 
760 				if (modifiable &&
761 				    !pullupmsg(mp, IPV6_HDR_LEN)) {
762 					return (-1);
763 				}
764 			}
765 
766 			ip6h = (ip6_t *)mp->b_rptr;
767 		}
768 
769 		if (!modifiable || !(OK_32PTR((char *)ip6h)) ||
770 		    ((unsigned char *)ip6h + IPV6_HDR_LEN > mp->b_wptr)) {
771 			/*
772 			 * If either ip6h is not alligned, or ip6h does not
773 			 * hold the complete ip6_t structure (a pullupmsg()
774 			 * is not an option since it would result in an
775 			 * unalligned ip6h), fanout to the default ring. Note
776 			 * that this may cause packets reordering.
777 			 */
778 			*indx = 0;
779 			*type = OTH;
780 			fanout_unalligned++;
781 			return (0);
782 		}
783 
784 		remlen = ntohs(ip6h->ip6_plen);
785 		nexthdr = ip6h->ip6_nxt;
786 
787 		if (remlen < MIN_EHDR_LEN)
788 			return (-1);
789 		/*
790 		 * Do src based fanout if below tunable is set to B_TRUE or
791 		 * when mac_ip_hdr_length_v6() fails because of malformed
792 		 * packets or because mblk's need to be concatenated using
793 		 * pullupmsg().
794 		 */
795 		if (mac_src_ipv6_fanout || !mac_ip_hdr_length_v6(mp, ip6h,
796 		    &hdr_len, &nexthdr)) {
797 			goto src_based_fanout;
798 		}
799 		whereptr = (uint8_t *)ip6h + hdr_len;
800 
801 		/* If the transport is one of below, we do port based fanout */
802 		switch (nexthdr) {
803 		case IPPROTO_TCP:
804 		case IPPROTO_UDP:
805 		case IPPROTO_SCTP:
806 		case IPPROTO_ESP:
807 			/*
808 			 * If the ports in the transport header is not part of
809 			 * the mblk, do src_based_fanout, instead of calling
810 			 * pullupmsg().
811 			 */
812 			if (mp->b_cont != NULL &&
813 			    whereptr + PORTS_SIZE > mp->b_wptr) {
814 				goto src_based_fanout;
815 			}
816 			break;
817 		default:
818 			break;
819 		}
820 
821 		switch (nexthdr) {
822 		case IPPROTO_TCP:
823 			hash = HASH_ADDR(V4_PART_OF_V6(ip6h->ip6_src),
824 			    *(uint32_t *)whereptr);
825 			*indx = COMPUTE_INDEX(hash,
826 			    mac_srs->srs_tcp_ring_count);
827 			*type = OTH;
828 			break;
829 
830 		case IPPROTO_UDP:
831 		case IPPROTO_SCTP:
832 		case IPPROTO_ESP:
833 			if (mac_fanout_type == MAC_FANOUT_DEFAULT) {
834 				hash = HASH_ADDR(V4_PART_OF_V6(ip6h->ip6_src),
835 				    *(uint32_t *)whereptr);
836 				*indx = COMPUTE_INDEX(hash,
837 				    mac_srs->srs_udp_ring_count);
838 			} else {
839 				*indx = mac_srs->srs_ind %
840 				    mac_srs->srs_udp_ring_count;
841 				mac_srs->srs_ind++;
842 			}
843 			*type = OTH;
844 			break;
845 
846 			/* For all other protocol, do source based fanout */
847 		default:
848 			goto src_based_fanout;
849 		}
850 	} else {
851 		*indx = 0;
852 		*type = OTH;
853 	}
854 	return (0);
855 
856 src_based_fanout:
857 	hash = HASH_ADDR(V4_PART_OF_V6(ip6h->ip6_src), (uint32_t)0);
858 	*indx = COMPUTE_INDEX(hash, mac_srs->srs_oth_ring_count);
859 	*type = OTH;
860 	return (0);
861 }
862 
863 /*
864  * mac_rx_srs_fanout
865  *
866  * This routine delivers packets destined to an SRS into a soft ring member
867  * of the set.
868  *
869  * Given a chain of packets we need to split it up into multiple sub chains
870  * destined for one of the TCP, UDP or OTH soft rings. Instead of entering
871  * the soft ring one packet at a time, we want to enter it in the form of a
872  * chain otherwise we get this start/stop behaviour where the worker thread
873  * goes to sleep and then next packets comes in forcing it to wake up etc.
874  *
875  * Note:
876  * Since we know what is the maximum fanout possible, we create a 2D array
877  * of 'softring types * MAX_SR_FANOUT' for the head, tail, cnt and sz
878  * variables so that we can enter the softrings with chain. We need the
879  * MAX_SR_FANOUT so we can allocate the arrays on the stack (a kmem_alloc
880  * for each packet would be expensive). If we ever want to have the
881  * ability to have unlimited fanout, we should probably declare a head,
882  * tail, cnt, sz with each soft ring (a data struct which contains a softring
883  * along with these members) and create an array of this uber struct so we
884  * don't have to do kmem_alloc.
885  */
886 int	fanout_oth1 = 0;
887 int	fanout_oth2 = 0;
888 int	fanout_oth3 = 0;
889 int	fanout_oth4 = 0;
890 int	fanout_oth5 = 0;
891 
892 static void
893 mac_rx_srs_fanout(mac_soft_ring_set_t *mac_srs, mblk_t *head)
894 {
895 	struct ether_header		*ehp;
896 	struct ether_vlan_header	*evhp;
897 	uint32_t			sap;
898 	ipha_t				*ipha;
899 	uint8_t				*dstaddr;
900 	uint_t				indx;
901 	size_t				ports_offset;
902 	size_t				ipha_len;
903 	size_t				hdrsize;
904 	uint_t				hash;
905 	mblk_t				*mp;
906 	mblk_t				*headmp[MAX_SR_TYPES][MAX_SR_FANOUT];
907 	mblk_t				*tailmp[MAX_SR_TYPES][MAX_SR_FANOUT];
908 	int				cnt[MAX_SR_TYPES][MAX_SR_FANOUT];
909 	size_t				sz[MAX_SR_TYPES][MAX_SR_FANOUT];
910 	size_t				sz1;
911 	boolean_t			bw_ctl;
912 	boolean_t			hw_classified;
913 	boolean_t			dls_bypass;
914 	boolean_t			is_ether;
915 	boolean_t			is_unicast;
916 	int				fanout_cnt;
917 	enum pkt_type			type;
918 	mac_client_impl_t		*mcip = mac_srs->srs_mcip;
919 
920 	is_ether = (mcip->mci_mip->mi_info.mi_nativemedia == DL_ETHER);
921 	bw_ctl = ((mac_srs->srs_type & SRST_BW_CONTROL) != 0);
922 
923 	/*
924 	 * If we don't have a Rx ring, S/W classification would have done
925 	 * its job and its a packet meant for us. If we were polling on
926 	 * the default ring (i.e. there was a ring assigned to this SRS),
927 	 * then we need to make sure that the mac address really belongs
928 	 * to us.
929 	 */
930 	hw_classified = mac_srs->srs_ring != NULL &&
931 	    mac_srs->srs_ring->mr_classify_type == MAC_HW_CLASSIFIER;
932 
933 	/*
934 	 * Special clients (eg. VLAN, non ether, etc) need DLS
935 	 * processing in the Rx path. SRST_DLS_BYPASS will be clear for
936 	 * such SRSs.
937 	 */
938 	dls_bypass = ((mac_srs->srs_type & SRST_DLS_BYPASS) != 0);
939 
940 	/*
941 	 * Since the softrings are never destroyed and we always
942 	 * create equal number of softrings for TCP, UDP and rest,
943 	 * its OK to check one of them for count and use it without
944 	 * any lock. In future, if soft rings get destroyed because
945 	 * of reduction in fanout, we will need to ensure that happens
946 	 * behind the SRS_PROC.
947 	 */
948 	fanout_cnt = mac_srs->srs_tcp_ring_count;
949 
950 	bzero(headmp, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (mblk_t *));
951 	bzero(tailmp, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (mblk_t *));
952 	bzero(cnt, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (int));
953 	bzero(sz, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (size_t));
954 
955 	/*
956 	 * We got a chain from SRS that we need to send to the soft rings.
957 	 * Since squeues for TCP & IPv4 sap poll their soft rings (for
958 	 * performance reasons), we need to separate out v4_tcp, v4_udp
959 	 * and the rest goes in other.
960 	 */
961 	while (head != NULL) {
962 		mp = head;
963 		head = head->b_next;
964 		mp->b_next = NULL;
965 
966 		type = OTH;
967 		sz1 = (mp->b_cont == NULL) ? MBLKL(mp) : msgdsize(mp);
968 
969 		if (is_ether) {
970 			/*
971 			 * At this point we can be sure the packet at least
972 			 * has an ether header.
973 			 */
974 			if (sz1 < sizeof (struct ether_header)) {
975 				mac_rx_drop_pkt(mac_srs, mp);
976 				continue;
977 			}
978 			ehp = (struct ether_header *)mp->b_rptr;
979 
980 			/*
981 			 * Determine if this is a VLAN or non-VLAN packet.
982 			 */
983 			if ((sap = ntohs(ehp->ether_type)) == VLAN_TPID) {
984 				evhp = (struct ether_vlan_header *)mp->b_rptr;
985 				sap = ntohs(evhp->ether_type);
986 				hdrsize = sizeof (struct ether_vlan_header);
987 				/*
988 				 * Check if the VID of the packet, if any,
989 				 * belongs to this client.
990 				 */
991 				if (!mac_client_check_flow_vid(mcip,
992 				    VLAN_ID(ntohs(evhp->ether_tci)))) {
993 					mac_rx_drop_pkt(mac_srs, mp);
994 					continue;
995 				}
996 			} else {
997 				hdrsize = sizeof (struct ether_header);
998 			}
999 			is_unicast =
1000 			    ((((uint8_t *)&ehp->ether_dhost)[0] & 0x01) == 0);
1001 			dstaddr = (uint8_t *)&ehp->ether_dhost;
1002 		} else {
1003 			mac_header_info_t		mhi;
1004 
1005 			if (mac_header_info((mac_handle_t)mcip->mci_mip,
1006 			    mp, &mhi) != 0) {
1007 				mac_rx_drop_pkt(mac_srs, mp);
1008 				continue;
1009 			}
1010 			hdrsize = mhi.mhi_hdrsize;
1011 			sap = mhi.mhi_bindsap;
1012 			is_unicast = (mhi.mhi_dsttype == MAC_ADDRTYPE_UNICAST);
1013 			dstaddr = (uint8_t *)mhi.mhi_daddr;
1014 		}
1015 
1016 		if (!dls_bypass) {
1017 			if (mac_rx_srs_long_fanout(mac_srs, mp, sap,
1018 			    hdrsize, &type, &indx) == -1) {
1019 				mac_rx_drop_pkt(mac_srs, mp);
1020 				continue;
1021 			}
1022 
1023 			FANOUT_ENQUEUE_MP(headmp[type][indx],
1024 			    tailmp[type][indx], cnt[type][indx], bw_ctl,
1025 			    sz[type][indx], sz1, mp);
1026 			continue;
1027 		}
1028 
1029 
1030 		/*
1031 		 * If we are using the default Rx ring where H/W or S/W
1032 		 * classification has not happened, we need to verify if
1033 		 * this unicast packet really belongs to us.
1034 		 */
1035 		if (sap == ETHERTYPE_IP) {
1036 			/*
1037 			 * If we are H/W classified, but we have promisc
1038 			 * on, then we need to check for the unicast address.
1039 			 */
1040 			if (hw_classified && mcip->mci_promisc_list != NULL) {
1041 				mac_address_t		*map;
1042 
1043 				rw_enter(&mcip->mci_rw_lock, RW_READER);
1044 				map = mcip->mci_unicast;
1045 				if (bcmp(dstaddr, map->ma_addr,
1046 				    map->ma_len) == 0)
1047 					type = UNDEF;
1048 				rw_exit(&mcip->mci_rw_lock);
1049 			} else if (is_unicast) {
1050 				type = UNDEF;
1051 			}
1052 		}
1053 
1054 		/*
1055 		 * This needs to become a contract with the driver for
1056 		 * the fast path.
1057 		 */
1058 
1059 		ipha = (ipha_t *)(mp->b_rptr + hdrsize);
1060 		if ((type != OTH) && MBLK_RX_FANOUT_SLOWPATH(mp, ipha)) {
1061 			type = OTH;
1062 			fanout_oth1++;
1063 		}
1064 
1065 		if (type != OTH) {
1066 			uint16_t	frag_offset_flags;
1067 
1068 			switch (ipha->ipha_protocol) {
1069 			case IPPROTO_TCP:
1070 			case IPPROTO_UDP:
1071 			case IPPROTO_SCTP:
1072 			case IPPROTO_ESP:
1073 				ipha_len = IPH_HDR_LENGTH(ipha);
1074 				if ((uchar_t *)ipha + ipha_len + PORTS_SIZE >
1075 				    mp->b_wptr) {
1076 					type = OTH;
1077 					break;
1078 				}
1079 				frag_offset_flags =
1080 				    ntohs(ipha->ipha_fragment_offset_and_flags);
1081 				if ((frag_offset_flags &
1082 				    (IPH_MF | IPH_OFFSET)) != 0) {
1083 					type = OTH;
1084 					fanout_oth3++;
1085 					break;
1086 				}
1087 				ports_offset = hdrsize + ipha_len;
1088 				break;
1089 			default:
1090 				type = OTH;
1091 				fanout_oth4++;
1092 				break;
1093 			}
1094 		}
1095 
1096 		if (type == OTH) {
1097 			if (mac_rx_srs_long_fanout(mac_srs, mp, sap,
1098 			    hdrsize, &type, &indx) == -1) {
1099 				mac_rx_drop_pkt(mac_srs, mp);
1100 				continue;
1101 			}
1102 
1103 			FANOUT_ENQUEUE_MP(headmp[type][indx],
1104 			    tailmp[type][indx], cnt[type][indx], bw_ctl,
1105 			    sz[type][indx], sz1, mp);
1106 			continue;
1107 		}
1108 
1109 		ASSERT(type == UNDEF);
1110 
1111 		/*
1112 		 * XXX-Sunay: We should hold srs_lock since ring_count
1113 		 * below can change. But if we are always called from
1114 		 * mac_rx_srs_drain and SRS_PROC is set, then we can
1115 		 * enforce that ring_count can't be changed i.e.
1116 		 * to change fanout type or ring count, the calling
1117 		 * thread needs to be behind SRS_PROC.
1118 		 */
1119 		switch (ipha->ipha_protocol) {
1120 		case IPPROTO_TCP:
1121 			/*
1122 			 * Note that for ESP, we fanout on SPI and it is at the
1123 			 * same offset as the 2x16-bit ports. So it is clumped
1124 			 * along with TCP, UDP and SCTP.
1125 			 */
1126 			hash = HASH_ADDR(ipha->ipha_src,
1127 			    *(uint32_t *)(mp->b_rptr + ports_offset));
1128 			indx = COMPUTE_INDEX(hash, mac_srs->srs_tcp_ring_count);
1129 			type = V4_TCP;
1130 			mp->b_rptr += hdrsize;
1131 			break;
1132 		case IPPROTO_UDP:
1133 		case IPPROTO_SCTP:
1134 		case IPPROTO_ESP:
1135 			if (mac_fanout_type == MAC_FANOUT_DEFAULT) {
1136 				hash = HASH_ADDR(ipha->ipha_src,
1137 				    *(uint32_t *)(mp->b_rptr + ports_offset));
1138 				indx = COMPUTE_INDEX(hash,
1139 				    mac_srs->srs_udp_ring_count);
1140 			} else {
1141 				indx = mac_srs->srs_ind %
1142 				    mac_srs->srs_udp_ring_count;
1143 				mac_srs->srs_ind++;
1144 			}
1145 			type = V4_UDP;
1146 			mp->b_rptr += hdrsize;
1147 			break;
1148 		default:
1149 			indx = 0;
1150 			type = OTH;
1151 		}
1152 
1153 		FANOUT_ENQUEUE_MP(headmp[type][indx], tailmp[type][indx],
1154 		    cnt[type][indx], bw_ctl, sz[type][indx], sz1, mp);
1155 	}
1156 
1157 	for (type = V4_TCP; type < UNDEF; type++) {
1158 		int	i;
1159 
1160 		for (i = 0; i < fanout_cnt; i++) {
1161 			if (headmp[type][i] != NULL) {
1162 				mac_soft_ring_t	*softring;
1163 
1164 				ASSERT(tailmp[type][i]->b_next == NULL);
1165 				switch (type) {
1166 				case V4_TCP:
1167 					softring =
1168 					    mac_srs->srs_tcp_soft_rings[i];
1169 					break;
1170 				case V4_UDP:
1171 					softring =
1172 					    mac_srs->srs_udp_soft_rings[i];
1173 					break;
1174 				case OTH:
1175 					softring =
1176 					    mac_srs->srs_oth_soft_rings[i];
1177 					break;
1178 				}
1179 				mac_rx_soft_ring_process(mcip,
1180 				    softring, headmp[type][i], tailmp[type][i],
1181 				    cnt[type][i], sz[type][i]);
1182 			}
1183 		}
1184 	}
1185 }
1186 
1187 #define	SRS_BYTES_TO_PICKUP	150000
1188 ssize_t	max_bytes_to_pickup = SRS_BYTES_TO_PICKUP;
1189 
1190 /*
1191  * mac_rx_srs_poll_ring
1192  *
1193  * This SRS Poll thread uses this routine to poll the underlying hardware
1194  * Rx ring to get a chain of packets. It can inline process that chain
1195  * if mac_latency_optimize is set (default) or signal the SRS worker thread
1196  * to do the remaining processing.
1197  *
1198  * Since packets come in the system via interrupt or poll path, we also
1199  * update the stats and deal with promiscous clients here.
1200  */
1201 void
1202 mac_rx_srs_poll_ring(mac_soft_ring_set_t *mac_srs)
1203 {
1204 	kmutex_t 		*lock = &mac_srs->srs_lock;
1205 	kcondvar_t 		*async = &mac_srs->srs_cv;
1206 	mac_srs_rx_t		*srs_rx = &mac_srs->srs_rx;
1207 	mblk_t 			*head, *tail, *mp;
1208 	callb_cpr_t 		cprinfo;
1209 	ssize_t 		bytes_to_pickup;
1210 	size_t 			sz;
1211 	int			count;
1212 	mac_client_impl_t	*smcip;
1213 
1214 	CALLB_CPR_INIT(&cprinfo, lock, callb_generic_cpr, "mac_srs_poll");
1215 	mutex_enter(lock);
1216 
1217 start:
1218 	for (;;) {
1219 		if (mac_srs->srs_state & SRS_PAUSE)
1220 			goto done;
1221 
1222 		CALLB_CPR_SAFE_BEGIN(&cprinfo);
1223 		cv_wait(async, lock);
1224 		CALLB_CPR_SAFE_END(&cprinfo, lock);
1225 
1226 		if (mac_srs->srs_state & SRS_PAUSE)
1227 			goto done;
1228 
1229 check_again:
1230 		if (mac_srs->srs_type & SRST_BW_CONTROL) {
1231 			/*
1232 			 * We pick as many bytes as we are allowed to queue.
1233 			 * Its possible that we will exceed the total
1234 			 * packets queued in case this SRS is part of the
1235 			 * Rx ring group since > 1 poll thread can be pulling
1236 			 * upto the max allowed packets at the same time
1237 			 * but that should be OK.
1238 			 */
1239 			mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1240 			bytes_to_pickup =
1241 			    mac_srs->srs_bw->mac_bw_drop_threshold -
1242 			    mac_srs->srs_bw->mac_bw_sz;
1243 			/*
1244 			 * We shouldn't have been signalled if we
1245 			 * have 0 or less bytes to pick but since
1246 			 * some of the bytes accounting is driver
1247 			 * dependant, we do the safety check.
1248 			 */
1249 			if (bytes_to_pickup < 0)
1250 				bytes_to_pickup = 0;
1251 			mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1252 		} else {
1253 			/*
1254 			 * ToDO: Need to change the polling API
1255 			 * to add a packet count and a flag which
1256 			 * tells the driver whether we want packets
1257 			 * based on a count, or bytes, or all the
1258 			 * packets queued in the driver/HW. This
1259 			 * way, we never have to check the limits
1260 			 * on poll path. We truly let only as many
1261 			 * packets enter the system as we are willing
1262 			 * to process or queue.
1263 			 *
1264 			 * Something along the lines of
1265 			 * pkts_to_pickup = mac_soft_ring_max_q_cnt -
1266 			 *	mac_srs->srs_poll_pkt_cnt
1267 			 */
1268 
1269 			/*
1270 			 * Since we are not doing B/W control, pick
1271 			 * as many packets as allowed.
1272 			 */
1273 			bytes_to_pickup = max_bytes_to_pickup;
1274 		}
1275 
1276 		/* Poll the underlying Hardware */
1277 		mutex_exit(lock);
1278 		head = MAC_HWRING_POLL(mac_srs->srs_ring, (int)bytes_to_pickup);
1279 		mutex_enter(lock);
1280 
1281 		ASSERT((mac_srs->srs_state & SRS_POLL_THR_OWNER) ==
1282 		    SRS_POLL_THR_OWNER);
1283 
1284 		mp = tail = head;
1285 		count = 0;
1286 		sz = 0;
1287 		while (mp != NULL) {
1288 			tail = mp;
1289 			sz += msgdsize(mp);
1290 			mp = mp->b_next;
1291 			count++;
1292 		}
1293 
1294 		if (head != NULL) {
1295 			tail->b_next = NULL;
1296 			smcip = mac_srs->srs_mcip;
1297 
1298 			if ((mac_srs->srs_type & SRST_FLOW) ||
1299 			    (smcip == NULL)) {
1300 				FLOW_STAT_UPDATE(mac_srs->srs_flent,
1301 				    rbytes, sz);
1302 				FLOW_STAT_UPDATE(mac_srs->srs_flent,
1303 				    ipackets, count);
1304 			}
1305 
1306 			/*
1307 			 * If there are any promiscuous mode callbacks
1308 			 * defined for this MAC client, pass them a copy
1309 			 * if appropriate and also update the counters.
1310 			 */
1311 			if (smcip != NULL) {
1312 				smcip->mci_stat_ibytes += sz;
1313 				smcip->mci_stat_ipackets += count;
1314 
1315 				if (smcip->mci_mip->mi_promisc_list != NULL) {
1316 					mutex_exit(lock);
1317 					mac_promisc_dispatch(smcip->mci_mip,
1318 					    head, NULL);
1319 					mutex_enter(lock);
1320 				}
1321 			}
1322 			if (mac_srs->srs_type & SRST_BW_CONTROL) {
1323 				mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1324 				mac_srs->srs_bw->mac_bw_polled += sz;
1325 				mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1326 			}
1327 			srs_rx->sr_poll_count += count;
1328 			MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, head, tail,
1329 			    count, sz);
1330 			if (count <= 10)
1331 				srs_rx->sr_chain_cnt_undr10++;
1332 			else if (count > 10 && count <= 50)
1333 				srs_rx->sr_chain_cnt_10to50++;
1334 			else
1335 				srs_rx->sr_chain_cnt_over50++;
1336 		}
1337 
1338 		/*
1339 		 * We are guaranteed that SRS_PROC will be set if we
1340 		 * are here. Also, poll thread gets to run only if
1341 		 * the drain was being done by a worker thread although
1342 		 * its possible that worker thread is still running
1343 		 * and poll thread was sent down to keep the pipeline
1344 		 * going instead of doing a complete drain and then
1345 		 * trying to poll the NIC.
1346 		 *
1347 		 * So we need to check SRS_WORKER flag to make sure
1348 		 * that the worker thread is not processing the queue
1349 		 * in parallel to us. The flags and conditions are
1350 		 * protected by the srs_lock to prevent any race. We
1351 		 * ensure that we don't drop the srs_lock from now
1352 		 * till the end and similarly we don't drop the srs_lock
1353 		 * in mac_rx_srs_drain() till similar condition check
1354 		 * are complete. The mac_rx_srs_drain() needs to ensure
1355 		 * that SRS_WORKER flag remains set as long as its
1356 		 * processing the queue.
1357 		 */
1358 		if (!(mac_srs->srs_state & SRS_WORKER) &&
1359 		    (mac_srs->srs_first != NULL)) {
1360 			/*
1361 			 * We have packets to process and worker thread
1362 			 * is not running. Check to see if poll thread is
1363 			 * allowed to process.
1364 			 */
1365 			if (mac_srs->srs_state & SRS_LATENCY_OPT) {
1366 				mac_srs->srs_drain_func(mac_srs, SRS_POLL_PROC);
1367 				if (!(mac_srs->srs_state & SRS_PAUSE) &&
1368 				    srs_rx->sr_poll_pkt_cnt <=
1369 				    srs_rx->sr_lowat) {
1370 					srs_rx->sr_poll_again++;
1371 					goto check_again;
1372 				}
1373 				/*
1374 				 * We are already above low water mark
1375 				 * so stay in the polling mode but no
1376 				 * need to poll. Once we dip below
1377 				 * the polling threshold, the processing
1378 				 * thread (soft ring) will signal us
1379 				 * to poll again (MAC_UPDATE_SRS_COUNT)
1380 				 */
1381 				srs_rx->sr_poll_drain_no_poll++;
1382 				mac_srs->srs_state &= ~(SRS_PROC|SRS_GET_PKTS);
1383 				/*
1384 				 * In B/W control case, its possible
1385 				 * that the backlog built up due to
1386 				 * B/W limit being reached and packets
1387 				 * are queued only in SRS. In this case,
1388 				 * we should schedule worker thread
1389 				 * since no one else will wake us up.
1390 				 */
1391 				if ((mac_srs->srs_type & SRST_BW_CONTROL) &&
1392 				    (mac_srs->srs_tid == NULL)) {
1393 					mac_srs->srs_tid =
1394 					    timeout(mac_srs_fire, mac_srs, 1);
1395 					srs_rx->sr_poll_worker_wakeup++;
1396 				}
1397 			} else {
1398 				/*
1399 				 * Wakeup the worker thread for more processing.
1400 				 * We optimize for throughput in this case.
1401 				 */
1402 				mac_srs->srs_state &= ~(SRS_PROC|SRS_GET_PKTS);
1403 				MAC_SRS_WORKER_WAKEUP(mac_srs);
1404 				srs_rx->sr_poll_sig_worker++;
1405 			}
1406 		} else if ((mac_srs->srs_first == NULL) &&
1407 		    !(mac_srs->srs_state & SRS_WORKER)) {
1408 			/*
1409 			 * There is nothing queued in SRS and
1410 			 * no worker thread running. Plus we
1411 			 * didn't get anything from the H/W
1412 			 * as well (head == NULL);
1413 			 */
1414 			ASSERT(head == NULL);
1415 			mac_srs->srs_state &=
1416 			    ~(SRS_PROC|SRS_GET_PKTS);
1417 
1418 			/*
1419 			 * If we have a packets in soft ring, don't allow
1420 			 * more packets to come into this SRS by keeping the
1421 			 * interrupts off but not polling the H/W. The
1422 			 * poll thread will get signaled as soon as
1423 			 * srs_poll_pkt_cnt dips below poll threshold.
1424 			 */
1425 			if (srs_rx->sr_poll_pkt_cnt == 0) {
1426 				srs_rx->sr_poll_intr_enable++;
1427 				MAC_SRS_POLLING_OFF(mac_srs);
1428 			} else {
1429 				/*
1430 				 * We know nothing is queued in SRS
1431 				 * since we are here after checking
1432 				 * srs_first is NULL. The backlog
1433 				 * is entirely due to packets queued
1434 				 * in Soft ring which will wake us up
1435 				 * and get the interface out of polling
1436 				 * mode once the backlog dips below
1437 				 * sr_poll_thres.
1438 				 */
1439 				srs_rx->sr_poll_no_poll++;
1440 			}
1441 		} else {
1442 			/*
1443 			 * Worker thread is already running.
1444 			 * Nothing much to do. If the polling
1445 			 * was enabled, worker thread will deal
1446 			 * with that.
1447 			 */
1448 			mac_srs->srs_state &= ~SRS_GET_PKTS;
1449 			srs_rx->sr_poll_goto_sleep++;
1450 		}
1451 	}
1452 done:
1453 	mac_srs->srs_state |= SRS_POLL_THR_QUIESCED;
1454 	cv_signal(&mac_srs->srs_async);
1455 	/*
1456 	 * If this is a temporary quiesce then wait for the restart signal
1457 	 * from the srs worker. Then clear the flags and signal the srs worker
1458 	 * to ensure a positive handshake and go back to start.
1459 	 */
1460 	while (!(mac_srs->srs_state & (SRS_CONDEMNED | SRS_POLL_THR_RESTART)))
1461 		cv_wait(async, lock);
1462 	if (mac_srs->srs_state & SRS_POLL_THR_RESTART) {
1463 		ASSERT(!(mac_srs->srs_state & SRS_CONDEMNED));
1464 		mac_srs->srs_state &=
1465 		    ~(SRS_POLL_THR_QUIESCED | SRS_POLL_THR_RESTART);
1466 		cv_signal(&mac_srs->srs_async);
1467 		goto start;
1468 	} else {
1469 		mac_srs->srs_state |= SRS_POLL_THR_EXITED;
1470 		cv_signal(&mac_srs->srs_async);
1471 		CALLB_CPR_EXIT(&cprinfo);
1472 		thread_exit();
1473 	}
1474 }
1475 
1476 /*
1477  * mac_srs_pick_chain
1478  *
1479  * In Bandwidth control case, checks how many packets can be processed
1480  * and return them in a sub chain.
1481  */
1482 static mblk_t *
1483 mac_srs_pick_chain(mac_soft_ring_set_t *mac_srs, mblk_t **chain_tail,
1484     size_t *chain_sz, int *chain_cnt)
1485 {
1486 	mblk_t 			*head = NULL;
1487 	mblk_t 			*tail = NULL;
1488 	size_t			sz;
1489 	size_t 			tsz = 0;
1490 	int			cnt = 0;
1491 	mblk_t 			*mp;
1492 
1493 	ASSERT(MUTEX_HELD(&mac_srs->srs_lock));
1494 	mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1495 	if (((mac_srs->srs_bw->mac_bw_used + mac_srs->srs_size) <=
1496 	    mac_srs->srs_bw->mac_bw_limit) ||
1497 	    (mac_srs->srs_bw->mac_bw_limit == 0)) {
1498 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1499 		head = mac_srs->srs_first;
1500 		mac_srs->srs_first = NULL;
1501 		*chain_tail = mac_srs->srs_last;
1502 		mac_srs->srs_last = NULL;
1503 		*chain_sz = mac_srs->srs_size;
1504 		*chain_cnt = mac_srs->srs_count;
1505 		mac_srs->srs_count = 0;
1506 		mac_srs->srs_size = 0;
1507 		return (head);
1508 	}
1509 
1510 	/*
1511 	 * Can't clear the entire backlog.
1512 	 * Need to find how many packets to pick
1513 	 */
1514 	ASSERT(MUTEX_HELD(&mac_srs->srs_bw->mac_bw_lock));
1515 	while ((mp = mac_srs->srs_first) != NULL) {
1516 		sz = msgdsize(mp);
1517 		if ((tsz + sz + mac_srs->srs_bw->mac_bw_used) >
1518 		    mac_srs->srs_bw->mac_bw_limit) {
1519 			if (!(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED))
1520 				mac_srs->srs_bw->mac_bw_state |=
1521 				    SRS_BW_ENFORCED;
1522 			break;
1523 		}
1524 
1525 		/*
1526 		 * The _size & cnt is  decremented from the softrings
1527 		 * when they send up the packet for polling to work
1528 		 * properly.
1529 		 */
1530 		tsz += sz;
1531 		cnt++;
1532 		mac_srs->srs_count--;
1533 		mac_srs->srs_size -= sz;
1534 		if (tail != NULL)
1535 			tail->b_next = mp;
1536 		else
1537 			head = mp;
1538 		tail = mp;
1539 		mac_srs->srs_first = mac_srs->srs_first->b_next;
1540 	}
1541 	mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1542 	if (mac_srs->srs_first == NULL)
1543 		mac_srs->srs_last = NULL;
1544 
1545 	if (tail != NULL)
1546 		tail->b_next = NULL;
1547 	*chain_tail = tail;
1548 	*chain_cnt = cnt;
1549 	*chain_sz = tsz;
1550 
1551 	return (head);
1552 }
1553 
1554 /*
1555  * mac_rx_srs_drain
1556  *
1557  * The SRS drain routine. Gets to run to clear the queue. Any thread
1558  * (worker, interrupt, poll) can call this based on processing model.
1559  * The first thing we do is disable interrupts if possible and then
1560  * drain the queue. we also try to poll the underlying hardware if
1561  * there is a dedicated hardware Rx ring assigned to this SRS.
1562  *
1563  * There is a equivalent drain routine in bandwidth control mode
1564  * mac_rx_srs_drain_bw. There is some code duplication between the two
1565  * routines but they are highly performance sensitive and are easier
1566  * to read/debug if they stay separate. Any code changes here might
1567  * also apply to mac_rx_srs_drain_bw as well.
1568  */
1569 void
1570 mac_rx_srs_drain(mac_soft_ring_set_t *mac_srs, uint_t proc_type)
1571 {
1572 	mblk_t 			*head;
1573 	mblk_t			*tail;
1574 	timeout_id_t 		tid;
1575 	int			cnt = 0;
1576 	mac_client_impl_t	*mcip = mac_srs->srs_mcip;
1577 	mac_srs_rx_t		*srs_rx = &mac_srs->srs_rx;
1578 
1579 	ASSERT(MUTEX_HELD(&mac_srs->srs_lock));
1580 	ASSERT(!(mac_srs->srs_type & SRST_BW_CONTROL));
1581 
1582 	/* If we are blanked i.e. can't do upcalls, then we are done */
1583 	if (mac_srs->srs_state & (SRS_BLANK | SRS_PAUSE)) {
1584 		ASSERT((mac_srs->srs_type & SRST_NO_SOFT_RINGS) ||
1585 		    (mac_srs->srs_state & SRS_PAUSE));
1586 		goto out;
1587 	}
1588 
1589 	if (mac_srs->srs_first == NULL)
1590 		goto out;
1591 
1592 	if (!(mac_srs->srs_state & SRS_LATENCY_OPT) &&
1593 	    (srs_rx->sr_poll_pkt_cnt <= srs_rx->sr_lowat)) {
1594 		/*
1595 		 * In the normal case, the SRS worker thread does no
1596 		 * work and we wait for a backlog to build up before
1597 		 * we switch into polling mode. In case we are
1598 		 * optimizing for throughput, we use the worker thread
1599 		 * as well. The goal is to let worker thread process
1600 		 * the queue and poll thread to feed packets into
1601 		 * the queue. As such, we should signal the poll
1602 		 * thread to try and get more packets.
1603 		 *
1604 		 * We could have pulled this check in the POLL_RING
1605 		 * macro itself but keeping it explicit here makes
1606 		 * the architecture more human understandable.
1607 		 */
1608 		MAC_SRS_POLL_RING(mac_srs);
1609 	}
1610 
1611 again:
1612 	head = mac_srs->srs_first;
1613 	mac_srs->srs_first = NULL;
1614 	tail = mac_srs->srs_last;
1615 	mac_srs->srs_last = NULL;
1616 	cnt = mac_srs->srs_count;
1617 	mac_srs->srs_count = 0;
1618 
1619 	ASSERT(head != NULL);
1620 	ASSERT(tail != NULL);
1621 
1622 	if ((tid = mac_srs->srs_tid) != 0)
1623 		mac_srs->srs_tid = 0;
1624 
1625 	mac_srs->srs_state |= (SRS_PROC|proc_type);
1626 
1627 
1628 	/*
1629 	 * mcip is NULL for broadcast and multicast flows. The promisc
1630 	 * callbacks for broadcast and multicast packets are delivered from
1631 	 * mac_rx() and we don't need to worry about that case in this path
1632 	 */
1633 	if (mcip != NULL && mcip->mci_promisc_list != NULL) {
1634 		mutex_exit(&mac_srs->srs_lock);
1635 		mac_promisc_client_dispatch(mcip, head);
1636 		mutex_enter(&mac_srs->srs_lock);
1637 	}
1638 
1639 	/*
1640 	 * Check if SRS itself is doing the processing
1641 	 * This direct path does not apply when subflows are present. In this
1642 	 * case, packets need to be dispatched to a soft ring according to the
1643 	 * flow's bandwidth and other resources contraints.
1644 	 */
1645 	if (mac_srs->srs_type & SRST_NO_SOFT_RINGS) {
1646 		mac_direct_rx_t		proc;
1647 		void			*arg1;
1648 		mac_resource_handle_t	arg2;
1649 
1650 		/*
1651 		 * This is the case when a Rx is directly
1652 		 * assigned and we have a fully classified
1653 		 * protocol chain. We can deal with it in
1654 		 * one shot.
1655 		 */
1656 		proc = srs_rx->sr_func;
1657 		arg1 = srs_rx->sr_arg1;
1658 		arg2 = srs_rx->sr_arg2;
1659 
1660 		mac_srs->srs_state |= SRS_CLIENT_PROC;
1661 		mutex_exit(&mac_srs->srs_lock);
1662 		if (tid != 0) {
1663 			(void) untimeout(tid);
1664 			tid = 0;
1665 		}
1666 
1667 		proc(arg1, arg2, head, NULL);
1668 		/*
1669 		 * Decrement the size and count here itelf
1670 		 * since the packet has been processed.
1671 		 */
1672 		mutex_enter(&mac_srs->srs_lock);
1673 		MAC_UPDATE_SRS_COUNT_LOCKED(mac_srs, cnt);
1674 		if (mac_srs->srs_state & SRS_CLIENT_WAIT)
1675 			cv_signal(&mac_srs->srs_client_cv);
1676 		mac_srs->srs_state &= ~SRS_CLIENT_PROC;
1677 	} else {
1678 		/* Some kind of softrings based fanout is required */
1679 		mutex_exit(&mac_srs->srs_lock);
1680 		if (tid != 0) {
1681 			(void) untimeout(tid);
1682 			tid = 0;
1683 		}
1684 
1685 		/*
1686 		 * Since the fanout routines can deal with chains,
1687 		 * shoot the entire chain up.
1688 		 */
1689 		if (mac_srs->srs_type & SRST_FANOUT_SRC_IP)
1690 			mac_rx_srs_fanout(mac_srs, head);
1691 		else
1692 			mac_rx_srs_proto_fanout(mac_srs, head);
1693 		mutex_enter(&mac_srs->srs_lock);
1694 	}
1695 
1696 	if (!(mac_srs->srs_state & (SRS_BLANK|SRS_PAUSE)) &&
1697 	    (mac_srs->srs_first != NULL)) {
1698 		/*
1699 		 * More packets arrived while we were clearing the
1700 		 * SRS. This can be possible because of one of
1701 		 * three conditions below:
1702 		 * 1) The driver is using multiple worker threads
1703 		 *    to send the packets to us.
1704 		 * 2) The driver has a race in switching
1705 		 *    between interrupt and polling mode or
1706 		 * 3) Packets are arriving in this SRS via the
1707 		 *    S/W classification as well.
1708 		 *
1709 		 * We should switch to polling mode and see if we
1710 		 * need to send the poll thread down. Also, signal
1711 		 * the worker thread to process whats just arrived.
1712 		 */
1713 		MAC_SRS_POLLING_ON(mac_srs);
1714 		if (srs_rx->sr_poll_pkt_cnt <= srs_rx->sr_lowat) {
1715 			srs_rx->sr_drain_poll_sig++;
1716 			MAC_SRS_POLL_RING(mac_srs);
1717 		}
1718 
1719 		/*
1720 		 * If we didn't signal the poll thread, we need
1721 		 * to deal with the pending packets ourselves.
1722 		 */
1723 		if (proc_type == SRS_WORKER) {
1724 			srs_rx->sr_drain_again++;
1725 			goto again;
1726 		} else {
1727 			srs_rx->sr_drain_worker_sig++;
1728 			cv_signal(&mac_srs->srs_async);
1729 		}
1730 	}
1731 
1732 out:
1733 	if (mac_srs->srs_state & SRS_GET_PKTS) {
1734 		/*
1735 		 * Poll thread is already running. Leave the
1736 		 * SRS_RPOC set and hand over the control to
1737 		 * poll thread.
1738 		 */
1739 		mac_srs->srs_state &= ~proc_type;
1740 		srs_rx->sr_drain_poll_running++;
1741 		return;
1742 	}
1743 
1744 	/*
1745 	 * Even if there are no packets queued in SRS, we
1746 	 * need to make sure that the shared counter is
1747 	 * clear and any associated softrings have cleared
1748 	 * all the backlog. Otherwise, leave the interface
1749 	 * in polling mode and the poll thread will get
1750 	 * signalled once the count goes down to zero.
1751 	 *
1752 	 * If someone is already draining the queue (SRS_PROC is
1753 	 * set) when the srs_poll_pkt_cnt goes down to zero,
1754 	 * then it means that drain is already running and we
1755 	 * will turn off polling at that time if there is
1756 	 * no backlog.
1757 	 *
1758 	 * As long as there are packets queued either
1759 	 * in soft ring set or its soft rings, we will leave
1760 	 * the interface in polling mode (even if the drain
1761 	 * was done being the interrupt thread). We signal
1762 	 * the poll thread as well if we have dipped below
1763 	 * low water mark.
1764 	 *
1765 	 * NOTE: We can't use the MAC_SRS_POLLING_ON macro
1766 	 * since that turn polling on only for worker thread.
1767 	 * Its not worth turning polling on for interrupt
1768 	 * thread (since NIC will not issue another interrupt)
1769 	 * unless a backlog builds up.
1770 	 */
1771 	if ((srs_rx->sr_poll_pkt_cnt > 0) &&
1772 	    (mac_srs->srs_state & SRS_POLLING_CAPAB)) {
1773 		mac_srs->srs_state &= ~(SRS_PROC|proc_type);
1774 		srs_rx->sr_drain_keep_polling++;
1775 		MAC_SRS_POLLING_ON(mac_srs);
1776 		if (srs_rx->sr_poll_pkt_cnt <= srs_rx->sr_lowat)
1777 			MAC_SRS_POLL_RING(mac_srs);
1778 		return;
1779 	}
1780 
1781 	/* Nothing else to do. Get out of poll mode */
1782 	MAC_SRS_POLLING_OFF(mac_srs);
1783 	mac_srs->srs_state &= ~(SRS_PROC|proc_type);
1784 	srs_rx->sr_drain_finish_intr++;
1785 }
1786 
1787 /*
1788  * mac_rx_srs_drain_bw
1789  *
1790  * The SRS BW drain routine. Gets to run to clear the queue. Any thread
1791  * (worker, interrupt, poll) can call this based on processing model.
1792  * The first thing we do is disable interrupts if possible and then
1793  * drain the queue. we also try to poll the underlying hardware if
1794  * there is a dedicated hardware Rx ring assigned to this SRS.
1795  *
1796  * There is a equivalent drain routine in non bandwidth control mode
1797  * mac_rx_srs_drain. There is some code duplication between the two
1798  * routines but they are highly performance sensitive and are easier
1799  * to read/debug if they stay separate. Any code changes here might
1800  * also apply to mac_rx_srs_drain as well.
1801  */
1802 void
1803 mac_rx_srs_drain_bw(mac_soft_ring_set_t *mac_srs, uint_t proc_type)
1804 {
1805 	mblk_t 			*head;
1806 	mblk_t			*tail;
1807 	timeout_id_t 		tid;
1808 	size_t			sz = 0;
1809 	int			cnt = 0;
1810 	mac_client_impl_t	*mcip = mac_srs->srs_mcip;
1811 	mac_srs_rx_t		*srs_rx = &mac_srs->srs_rx;
1812 
1813 	ASSERT(MUTEX_HELD(&mac_srs->srs_lock));
1814 	ASSERT(mac_srs->srs_type & SRST_BW_CONTROL);
1815 again:
1816 	/* Check if we are doing B/W control */
1817 	mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1818 	if (mac_srs->srs_bw->mac_bw_curr_time != lbolt) {
1819 		mac_srs->srs_bw->mac_bw_curr_time = lbolt;
1820 		mac_srs->srs_bw->mac_bw_used = 0;
1821 		if (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)
1822 			mac_srs->srs_bw->mac_bw_state &= ~SRS_BW_ENFORCED;
1823 	} else if (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED) {
1824 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1825 		goto done;
1826 	} else if (mac_srs->srs_bw->mac_bw_used >
1827 	    mac_srs->srs_bw->mac_bw_limit) {
1828 		mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
1829 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1830 		goto done;
1831 	}
1832 	mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1833 
1834 	/* If we are blanked i.e. can't do upcalls, then we are done */
1835 	if (mac_srs->srs_state & (SRS_BLANK | SRS_PAUSE)) {
1836 		ASSERT((mac_srs->srs_type & SRST_NO_SOFT_RINGS) ||
1837 		    (mac_srs->srs_state & SRS_PAUSE));
1838 		goto done;
1839 	}
1840 
1841 	sz = 0;
1842 	cnt = 0;
1843 	if ((head = mac_srs_pick_chain(mac_srs, &tail, &sz, &cnt)) == NULL) {
1844 		/*
1845 		 * We couldn't pick up a single packet.
1846 		 */
1847 		mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1848 		if ((mac_srs->srs_bw->mac_bw_used == 0) &&
1849 		    (mac_srs->srs_size != 0) &&
1850 		    !(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)) {
1851 			/*
1852 			 * Seems like configured B/W doesn't
1853 			 * even allow processing of 1 packet
1854 			 * per tick.
1855 			 *
1856 			 * XXX: raise the limit to processing
1857 			 * at least 1 packet per tick.
1858 			 */
1859 			mac_srs->srs_bw->mac_bw_limit +=
1860 			    mac_srs->srs_bw->mac_bw_limit;
1861 			mac_srs->srs_bw->mac_bw_drop_threshold +=
1862 			    mac_srs->srs_bw->mac_bw_drop_threshold;
1863 			cmn_err(CE_NOTE, "mac_rx_srs_drain: srs(%p) "
1864 			    "raised B/W limit to %d since not even a "
1865 			    "single packet can be processed per "
1866 			    "tick %d\n", (void *)mac_srs,
1867 			    (int)mac_srs->srs_bw->mac_bw_limit,
1868 			    (int)msgdsize(mac_srs->srs_first));
1869 		}
1870 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1871 		goto done;
1872 	}
1873 
1874 	ASSERT(head != NULL);
1875 	ASSERT(tail != NULL);
1876 
1877 	/* zero bandwidth: drop all and return to interrupt mode */
1878 	mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1879 	if (mac_srs->srs_bw->mac_bw_limit == 0) {
1880 		srs_rx->sr_drop_count += cnt;
1881 		ASSERT(mac_srs->srs_bw->mac_bw_sz >= sz);
1882 		mac_srs->srs_bw->mac_bw_sz -= sz;
1883 		mac_srs->srs_bw->mac_bw_drop_bytes += sz;
1884 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1885 		mac_pkt_drop(NULL, NULL, head, B_FALSE);
1886 		goto leave_poll;
1887 	} else {
1888 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1889 	}
1890 
1891 	if ((tid = mac_srs->srs_tid) != 0)
1892 		mac_srs->srs_tid = 0;
1893 
1894 	mac_srs->srs_state |= (SRS_PROC|proc_type);
1895 	MAC_SRS_WORKER_POLLING_ON(mac_srs);
1896 
1897 	/*
1898 	 * mcip is NULL for broadcast and multicast flows. The promisc
1899 	 * callbacks for broadcast and multicast packets are delivered from
1900 	 * mac_rx() and we don't need to worry about that case in this path
1901 	 */
1902 	if (mcip != NULL && mcip->mci_promisc_list != NULL) {
1903 		mutex_exit(&mac_srs->srs_lock);
1904 		mac_promisc_client_dispatch(mcip, head);
1905 		mutex_enter(&mac_srs->srs_lock);
1906 	}
1907 
1908 	/*
1909 	 * Check if SRS itself is doing the processing
1910 	 * This direct path does not apply when subflows are present. In this
1911 	 * case, packets need to be dispatched to a soft ring according to the
1912 	 * flow's bandwidth and other resources contraints.
1913 	 */
1914 	if (mac_srs->srs_type & SRST_NO_SOFT_RINGS) {
1915 		mac_direct_rx_t		proc;
1916 		void			*arg1;
1917 		mac_resource_handle_t	arg2;
1918 
1919 		/*
1920 		 * This is the case when a Rx is directly
1921 		 * assigned and we have a fully classified
1922 		 * protocol chain. We can deal with it in
1923 		 * one shot.
1924 		 */
1925 		proc = srs_rx->sr_func;
1926 		arg1 = srs_rx->sr_arg1;
1927 		arg2 = srs_rx->sr_arg2;
1928 
1929 		mac_srs->srs_state |= SRS_CLIENT_PROC;
1930 		mutex_exit(&mac_srs->srs_lock);
1931 		if (tid != 0) {
1932 			(void) untimeout(tid);
1933 			tid = 0;
1934 		}
1935 
1936 		proc(arg1, arg2, head, NULL);
1937 		/*
1938 		 * Decrement the size and count here itelf
1939 		 * since the packet has been processed.
1940 		 */
1941 		mutex_enter(&mac_srs->srs_lock);
1942 		MAC_UPDATE_SRS_COUNT_LOCKED(mac_srs, cnt);
1943 		MAC_UPDATE_SRS_SIZE_LOCKED(mac_srs, sz);
1944 
1945 		if (mac_srs->srs_state & SRS_CLIENT_WAIT)
1946 			cv_signal(&mac_srs->srs_client_cv);
1947 		mac_srs->srs_state &= ~SRS_CLIENT_PROC;
1948 	} else {
1949 		/* Some kind of softrings based fanout is required */
1950 		mutex_exit(&mac_srs->srs_lock);
1951 		if (tid != 0) {
1952 			(void) untimeout(tid);
1953 			tid = 0;
1954 		}
1955 
1956 		/*
1957 		 * Since the fanout routines can deal with chains,
1958 		 * shoot the entire chain up.
1959 		 */
1960 		if (mac_srs->srs_type & SRST_FANOUT_SRC_IP)
1961 			mac_rx_srs_fanout(mac_srs, head);
1962 		else
1963 			mac_rx_srs_proto_fanout(mac_srs, head);
1964 		mutex_enter(&mac_srs->srs_lock);
1965 	}
1966 
1967 	/*
1968 	 * Send the poll thread to pick up any packets arrived
1969 	 * so far. This also serves as the last check in case
1970 	 * nothing else is queued in the SRS. The poll thread
1971 	 * is signalled only in the case the drain was done
1972 	 * by the worker thread and SRS_WORKER is set. The
1973 	 * worker thread can run in parallel as long as the
1974 	 * SRS_WORKER flag is set. We we have nothing else to
1975 	 * process, we can exit while leaving SRS_PROC set
1976 	 * which gives the poll thread control to process and
1977 	 * cleanup once it returns from the NIC.
1978 	 *
1979 	 * If we have nothing else to process, we need to
1980 	 * ensure that we keep holding the srs_lock till
1981 	 * all the checks below are done and control is
1982 	 * handed to the poll thread if it was running.
1983 	 */
1984 	mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1985 	if (!(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)) {
1986 		if (mac_srs->srs_first != NULL) {
1987 			if (proc_type == SRS_WORKER) {
1988 				mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1989 				if (srs_rx->sr_poll_pkt_cnt <=
1990 				    srs_rx->sr_lowat)
1991 					MAC_SRS_POLL_RING(mac_srs);
1992 				goto again;
1993 			} else {
1994 				cv_signal(&mac_srs->srs_async);
1995 			}
1996 		}
1997 	}
1998 	mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1999 
2000 done:
2001 
2002 	if (mac_srs->srs_state & SRS_GET_PKTS) {
2003 		/*
2004 		 * Poll thread is already running. Leave the
2005 		 * SRS_RPOC set and hand over the control to
2006 		 * poll thread.
2007 		 */
2008 		mac_srs->srs_state &= ~proc_type;
2009 		return;
2010 	}
2011 
2012 	/*
2013 	 * If we can't process packets because we have exceeded
2014 	 * B/W limit for this tick, just set the timeout
2015 	 * and leave.
2016 	 *
2017 	 * Even if there are no packets queued in SRS, we
2018 	 * need to make sure that the shared counter is
2019 	 * clear and any associated softrings have cleared
2020 	 * all the backlog. Otherwise, leave the interface
2021 	 * in polling mode and the poll thread will get
2022 	 * signalled once the count goes down to zero.
2023 	 *
2024 	 * If someone is already draining the queue (SRS_PROC is
2025 	 * set) when the srs_poll_pkt_cnt goes down to zero,
2026 	 * then it means that drain is already running and we
2027 	 * will turn off polling at that time if there is
2028 	 * no backlog. As long as there are packets queued either
2029 	 * is soft ring set or its soft rings, we will leave
2030 	 * the interface in polling mode.
2031 	 */
2032 	mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
2033 	if ((mac_srs->srs_state & SRS_POLLING_CAPAB) &&
2034 	    ((mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED) ||
2035 	    (srs_rx->sr_poll_pkt_cnt > 0))) {
2036 		MAC_SRS_POLLING_ON(mac_srs);
2037 		mac_srs->srs_state &= ~(SRS_PROC|proc_type);
2038 		if ((mac_srs->srs_first != NULL) &&
2039 		    (mac_srs->srs_tid == NULL))
2040 			mac_srs->srs_tid = timeout(mac_srs_fire,
2041 			    mac_srs, 1);
2042 		mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
2043 		return;
2044 	}
2045 	mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
2046 
2047 leave_poll:
2048 
2049 	/* Nothing else to do. Get out of poll mode */
2050 	MAC_SRS_POLLING_OFF(mac_srs);
2051 	mac_srs->srs_state &= ~(SRS_PROC|proc_type);
2052 }
2053 
2054 /*
2055  * mac_srs_worker
2056  *
2057  * The SRS worker routine. Drains the queue when no one else is
2058  * processing it.
2059  */
2060 void
2061 mac_srs_worker(mac_soft_ring_set_t *mac_srs)
2062 {
2063 	kmutex_t 		*lock = &mac_srs->srs_lock;
2064 	kcondvar_t 		*async = &mac_srs->srs_async;
2065 	callb_cpr_t		cprinfo;
2066 	boolean_t		bw_ctl_flag;
2067 
2068 	CALLB_CPR_INIT(&cprinfo, lock, callb_generic_cpr, "srs_worker");
2069 	mutex_enter(lock);
2070 
2071 start:
2072 	for (;;) {
2073 		bw_ctl_flag = B_FALSE;
2074 		if (mac_srs->srs_type & SRST_BW_CONTROL) {
2075 			MAC_SRS_BW_LOCK(mac_srs);
2076 			MAC_SRS_CHECK_BW_CONTROL(mac_srs);
2077 			if (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)
2078 				bw_ctl_flag = B_TRUE;
2079 			MAC_SRS_BW_UNLOCK(mac_srs);
2080 		}
2081 		/*
2082 		 * The SRS_BW_ENFORCED flag may change since we have dropped
2083 		 * the mac_bw_lock. However the drain function can handle both
2084 		 * a drainable SRS or a bandwidth controlled SRS, and the
2085 		 * effect of scheduling a timeout is to wakeup the worker
2086 		 * thread which in turn will call the drain function. Since
2087 		 * we release the srs_lock atomically only in the cv_wait there
2088 		 * isn't a fear of waiting for ever.
2089 		 */
2090 		while (((mac_srs->srs_state & SRS_PROC) ||
2091 		    (mac_srs->srs_first == NULL) || bw_ctl_flag ||
2092 		    (mac_srs->srs_state & SRS_TX_BLOCKED)) &&
2093 		    !(mac_srs->srs_state & SRS_PAUSE)) {
2094 			/*
2095 			 * If we have packets queued and we are here
2096 			 * because B/W control is in place, we better
2097 			 * schedule the worker wakeup after 1 tick
2098 			 * to see if bandwidth control can be relaxed.
2099 			 */
2100 			if (bw_ctl_flag && mac_srs->srs_tid == NULL) {
2101 				/*
2102 				 * We need to ensure that a timer  is already
2103 				 * scheduled or we force  schedule one for
2104 				 * later so that we can continue processing
2105 				 * after this  quanta is over.
2106 				 */
2107 				mac_srs->srs_tid = timeout(mac_srs_fire,
2108 				    mac_srs, 1);
2109 			}
2110 wait:
2111 			CALLB_CPR_SAFE_BEGIN(&cprinfo);
2112 			cv_wait(async, lock);
2113 			CALLB_CPR_SAFE_END(&cprinfo, lock);
2114 
2115 			if (mac_srs->srs_state & SRS_PAUSE)
2116 				goto done;
2117 			if (mac_srs->srs_state & SRS_PROC)
2118 				goto wait;
2119 
2120 			if (mac_srs->srs_first != NULL &&
2121 			    mac_srs->srs_type & SRST_BW_CONTROL) {
2122 				MAC_SRS_BW_LOCK(mac_srs);
2123 				if (mac_srs->srs_bw->mac_bw_state &
2124 				    SRS_BW_ENFORCED) {
2125 					MAC_SRS_CHECK_BW_CONTROL(mac_srs);
2126 				}
2127 				bw_ctl_flag = mac_srs->srs_bw->mac_bw_state &
2128 				    SRS_BW_ENFORCED;
2129 				MAC_SRS_BW_UNLOCK(mac_srs);
2130 			}
2131 		}
2132 
2133 		if (mac_srs->srs_state & SRS_PAUSE)
2134 			goto done;
2135 		mac_srs->srs_drain_func(mac_srs, SRS_WORKER);
2136 	}
2137 done:
2138 	/*
2139 	 * The Rx SRS quiesce logic first cuts off packet supply to the SRS
2140 	 * from both hard and soft classifications and waits for such threads
2141 	 * to finish before signaling the worker. So at this point the only
2142 	 * thread left that could be competing with the worker is the poll
2143 	 * thread. In the case of Tx, there shouldn't be any thread holding
2144 	 * SRS_PROC at this point.
2145 	 */
2146 	if (!(mac_srs->srs_state & SRS_PROC)) {
2147 		mac_srs->srs_state |= SRS_PROC;
2148 	} else {
2149 		ASSERT((mac_srs->srs_type & SRST_TX) == 0);
2150 		/*
2151 		 * Poll thread still owns the SRS and is still running
2152 		 */
2153 		ASSERT((mac_srs->srs_poll_thr == NULL) ||
2154 		    ((mac_srs->srs_state & SRS_POLL_THR_OWNER) ==
2155 		    SRS_POLL_THR_OWNER));
2156 	}
2157 	mac_srs_worker_quiesce(mac_srs);
2158 	/*
2159 	 * Wait for the SRS_RESTART or SRS_CONDEMNED signal from the initiator
2160 	 * of the quiesce operation
2161 	 */
2162 	while (!(mac_srs->srs_state & (SRS_CONDEMNED | SRS_RESTART)))
2163 		cv_wait(&mac_srs->srs_async, &mac_srs->srs_lock);
2164 
2165 	if (mac_srs->srs_state & SRS_RESTART) {
2166 		ASSERT(!(mac_srs->srs_state & SRS_CONDEMNED));
2167 		mac_srs_worker_restart(mac_srs);
2168 		mac_srs->srs_state &= ~SRS_PROC;
2169 		goto start;
2170 	}
2171 
2172 	if (!(mac_srs->srs_state & SRS_CONDEMNED_DONE))
2173 		mac_srs_worker_quiesce(mac_srs);
2174 
2175 	mac_srs->srs_state &= ~SRS_PROC;
2176 	/* The macro drops the srs_lock */
2177 	CALLB_CPR_EXIT(&cprinfo);
2178 	thread_exit();
2179 }
2180 
2181 /*
2182  * mac_rx_srs_subflow_process
2183  *
2184  * Receive side routine called from interrupt path when there are
2185  * sub flows present on this SRS.
2186  */
2187 /* ARGSUSED */
2188 void
2189 mac_rx_srs_subflow_process(void *arg, mac_resource_handle_t srs,
2190     mblk_t *mp_chain, boolean_t loopback)
2191 {
2192 	flow_entry_t		*flent = NULL;
2193 	flow_entry_t		*prev_flent = NULL;
2194 	mblk_t			*mp = NULL;
2195 	mblk_t			*tail = NULL;
2196 	mac_soft_ring_set_t	*mac_srs = (mac_soft_ring_set_t *)srs;
2197 	mac_client_impl_t	*mcip;
2198 
2199 	mcip = mac_srs->srs_mcip;
2200 	ASSERT(mcip != NULL);
2201 
2202 	/*
2203 	 * We need to determine the SRS for every packet
2204 	 * by walking the flow table, if we don't get any,
2205 	 * then we proceed using the SRS we came with.
2206 	 */
2207 	mp = tail = mp_chain;
2208 	while (mp != NULL) {
2209 
2210 		/*
2211 		 * We will increment the stats for the mactching subflow.
2212 		 * when we get the bytes/pkt count for the classified packets
2213 		 * later in mac_rx_srs_process.
2214 		 */
2215 		(void) mac_flow_lookup(mcip->mci_subflow_tab, mp,
2216 		    FLOW_INBOUND, &flent);
2217 
2218 		if (mp == mp_chain || flent == prev_flent) {
2219 			if (prev_flent != NULL)
2220 				FLOW_REFRELE(prev_flent);
2221 			prev_flent = flent;
2222 			flent = NULL;
2223 			tail = mp;
2224 			mp = mp->b_next;
2225 			continue;
2226 		}
2227 		tail->b_next = NULL;
2228 		/*
2229 		 * A null indicates, this is for the mac_srs itself.
2230 		 * XXX-venu : probably assert for fe_rx_srs_cnt == 0.
2231 		 */
2232 		if (prev_flent == NULL || prev_flent->fe_rx_srs_cnt == 0) {
2233 			mac_rx_srs_process(arg,
2234 			    (mac_resource_handle_t)mac_srs, mp_chain,
2235 			    loopback);
2236 		} else {
2237 			(prev_flent->fe_cb_fn)(prev_flent->fe_cb_arg1,
2238 			    prev_flent->fe_cb_arg2, mp_chain, loopback);
2239 			FLOW_REFRELE(prev_flent);
2240 		}
2241 		prev_flent = flent;
2242 		flent = NULL;
2243 		mp_chain = mp;
2244 		tail = mp;
2245 		mp = mp->b_next;
2246 	}
2247 	/* Last chain */
2248 	ASSERT(mp_chain != NULL);
2249 	if (prev_flent == NULL || prev_flent->fe_rx_srs_cnt == 0) {
2250 		mac_rx_srs_process(arg,
2251 		    (mac_resource_handle_t)mac_srs, mp_chain, loopback);
2252 	} else {
2253 		(prev_flent->fe_cb_fn)(prev_flent->fe_cb_arg1,
2254 		    prev_flent->fe_cb_arg2, mp_chain, loopback);
2255 		FLOW_REFRELE(prev_flent);
2256 	}
2257 }
2258 
2259 /*
2260  * mac_rx_srs_process
2261  *
2262  * Receive side routine called from the interrupt path.
2263  *
2264  * loopback is set to force a context switch on the loopback
2265  * path between MAC clients.
2266  */
2267 /* ARGSUSED */
2268 void
2269 mac_rx_srs_process(void *arg, mac_resource_handle_t srs, mblk_t *mp_chain,
2270     boolean_t loopback)
2271 {
2272 	mac_soft_ring_set_t	*mac_srs = (mac_soft_ring_set_t *)srs;
2273 	mblk_t			*mp, *tail, *head;
2274 	int			count = 0;
2275 	int			count1;
2276 	size_t			sz = 0;
2277 	size_t			chain_sz, sz1;
2278 	mac_bw_ctl_t		*mac_bw;
2279 	mac_client_impl_t	*smcip;
2280 	mac_srs_rx_t		*srs_rx = &mac_srs->srs_rx;
2281 
2282 	/*
2283 	 * Set the tail, count and sz. We set the sz irrespective
2284 	 * of whether we are doing B/W control or not for the
2285 	 * purpose of updating the stats.
2286 	 */
2287 	mp = tail = mp_chain;
2288 	while (mp != NULL) {
2289 		tail = mp;
2290 		count++;
2291 		sz += msgdsize(mp);
2292 		mp = mp->b_next;
2293 	}
2294 
2295 	mutex_enter(&mac_srs->srs_lock);
2296 	smcip = mac_srs->srs_mcip;
2297 
2298 	if (mac_srs->srs_type & SRST_FLOW || smcip == NULL) {
2299 		FLOW_STAT_UPDATE(mac_srs->srs_flent, rbytes, sz);
2300 		FLOW_STAT_UPDATE(mac_srs->srs_flent, ipackets, count);
2301 	}
2302 	if (smcip != NULL) {
2303 		smcip->mci_stat_ibytes += sz;
2304 		smcip->mci_stat_ipackets += count;
2305 	}
2306 
2307 	/*
2308 	 * If the SRS in already being processed; has been blanked;
2309 	 * can be processed by worker thread only; or the B/W limit
2310 	 * has been reached, then queue the chain and check if
2311 	 * worker thread needs to be awakend.
2312 	 */
2313 	if (mac_srs->srs_type & SRST_BW_CONTROL) {
2314 		mac_bw = mac_srs->srs_bw;
2315 		ASSERT(mac_bw != NULL);
2316 		mutex_enter(&mac_bw->mac_bw_lock);
2317 		/* Count the packets and bytes via interrupt */
2318 		srs_rx->sr_intr_count += count;
2319 		mac_bw->mac_bw_intr += sz;
2320 		if (mac_bw->mac_bw_limit == 0) {
2321 			/* zero bandwidth: drop all */
2322 			srs_rx->sr_drop_count += count;
2323 			mac_bw->mac_bw_drop_bytes += sz;
2324 			mutex_exit(&mac_bw->mac_bw_lock);
2325 			mutex_exit(&mac_srs->srs_lock);
2326 			mac_pkt_drop(NULL, NULL, mp_chain, B_FALSE);
2327 			return;
2328 		} else {
2329 			if ((mac_bw->mac_bw_sz + sz) <=
2330 			    mac_bw->mac_bw_drop_threshold) {
2331 				mutex_exit(&mac_bw->mac_bw_lock);
2332 				MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, mp_chain,
2333 				    tail, count, sz);
2334 			} else {
2335 				mp = mp_chain;
2336 				chain_sz = 0;
2337 				count1 = 0;
2338 				tail = NULL;
2339 				head = NULL;
2340 				while (mp != NULL) {
2341 					sz1 = msgdsize(mp);
2342 					if (mac_bw->mac_bw_sz + chain_sz + sz1 >
2343 					    mac_bw->mac_bw_drop_threshold)
2344 						break;
2345 					chain_sz += sz1;
2346 					count1++;
2347 					tail = mp;
2348 					mp = mp->b_next;
2349 				}
2350 				mutex_exit(&mac_bw->mac_bw_lock);
2351 				if (tail != NULL) {
2352 					head = tail->b_next;
2353 					tail->b_next = NULL;
2354 					MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs,
2355 					    mp_chain, tail, count1, chain_sz);
2356 					sz -= chain_sz;
2357 					count -= count1;
2358 				} else {
2359 					/* Can't pick up any */
2360 					head = mp_chain;
2361 				}
2362 				if (head != NULL) {
2363 					/* Drop any packet over the threshold */
2364 					srs_rx->sr_drop_count += count;
2365 					mutex_enter(&mac_bw->mac_bw_lock);
2366 					mac_bw->mac_bw_drop_bytes += sz;
2367 					mutex_exit(&mac_bw->mac_bw_lock);
2368 					freemsgchain(head);
2369 				}
2370 			}
2371 			MAC_SRS_WORKER_WAKEUP(mac_srs);
2372 			mutex_exit(&mac_srs->srs_lock);
2373 			return;
2374 		}
2375 	}
2376 
2377 	/*
2378 	 * If the total number of packets queued in the SRS and
2379 	 * its associated soft rings exceeds the max allowed,
2380 	 * then drop the chain. If we are polling capable, this
2381 	 * shouldn't be happening.
2382 	 */
2383 	if (!(mac_srs->srs_type & SRST_BW_CONTROL) &&
2384 	    (srs_rx->sr_poll_pkt_cnt > srs_rx->sr_hiwat)) {
2385 		mac_bw = mac_srs->srs_bw;
2386 		srs_rx->sr_drop_count += count;
2387 		mutex_enter(&mac_bw->mac_bw_lock);
2388 		mac_bw->mac_bw_drop_bytes += sz;
2389 		mutex_exit(&mac_bw->mac_bw_lock);
2390 		freemsgchain(mp_chain);
2391 		mutex_exit(&mac_srs->srs_lock);
2392 		return;
2393 	}
2394 
2395 	MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, mp_chain, tail, count, sz);
2396 	/* Count the packets entering via interrupt path */
2397 	srs_rx->sr_intr_count += count;
2398 
2399 	if (!(mac_srs->srs_state & SRS_PROC)) {
2400 		/*
2401 		 * If we are coming via loopback or if we are not
2402 		 * optimizing for latency, we should signal the
2403 		 * worker thread.
2404 		 */
2405 		if (loopback || !(mac_srs->srs_state & SRS_LATENCY_OPT)) {
2406 			/*
2407 			 * For loopback, We need to let the worker take
2408 			 * over as we don't want to continue in the same
2409 			 * thread even if we can. This could lead to stack
2410 			 * overflows and may also end up using
2411 			 * resources (cpu) incorrectly.
2412 			 */
2413 			cv_signal(&mac_srs->srs_async);
2414 		} else {
2415 			/*
2416 			 * Seems like no one is processing the SRS and
2417 			 * there is no backlog. We also inline process
2418 			 * our packet if its a single packet in non
2419 			 * latency optimized case (in latency optimized
2420 			 * case, we inline process chains of any size).
2421 			 */
2422 			mac_srs->srs_drain_func(mac_srs, SRS_PROC_FAST);
2423 		}
2424 	}
2425 	mutex_exit(&mac_srs->srs_lock);
2426 }
2427 
2428 /* TX SIDE ROUTINES (RUNTIME) */
2429 
2430 /*
2431  * mac_tx_srs_no_desc
2432  *
2433  * This routine is called by Tx single ring default mode
2434  * when Tx ring runs out of descs.
2435  */
2436 mac_tx_cookie_t
2437 mac_tx_srs_no_desc(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2438     uint16_t flag, mblk_t **ret_mp)
2439 {
2440 	mac_tx_cookie_t cookie = NULL;
2441 	mac_srs_tx_t *srs_tx = &mac_srs->srs_tx;
2442 	boolean_t wakeup_worker = B_TRUE;
2443 	uint32_t tx_mode = srs_tx->st_mode;
2444 	int cnt, sz;
2445 	mblk_t *tail;
2446 
2447 	ASSERT(tx_mode == SRS_TX_DEFAULT || tx_mode == SRS_TX_BW);
2448 	if (flag & MAC_DROP_ON_NO_DESC) {
2449 		MAC_TX_SRS_DROP_MESSAGE(mac_srs, mp_chain, cookie);
2450 	} else {
2451 		if (mac_srs->srs_first != NULL)
2452 			wakeup_worker = B_FALSE;
2453 		MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2454 		if (flag & MAC_TX_NO_ENQUEUE) {
2455 			/*
2456 			 * If TX_QUEUED is not set, queue the
2457 			 * packet and let mac_tx_srs_drain()
2458 			 * set the TX_BLOCKED bit for the
2459 			 * reasons explained above. Otherwise,
2460 			 * return the mblks.
2461 			 */
2462 			if (wakeup_worker) {
2463 				MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2464 				    mp_chain, tail, cnt, sz);
2465 			} else {
2466 				MAC_TX_SET_NO_ENQUEUE(mac_srs,
2467 				    mp_chain, ret_mp, cookie);
2468 			}
2469 		} else {
2470 			MAC_TX_SRS_TEST_HIWAT(mac_srs, mp_chain,
2471 			    tail, cnt, sz, cookie);
2472 		}
2473 		if (wakeup_worker)
2474 			cv_signal(&mac_srs->srs_async);
2475 	}
2476 	return (cookie);
2477 }
2478 
2479 /*
2480  * mac_tx_srs_enqueue
2481  *
2482  * This routine is called when Tx SRS is operating in either serializer
2483  * or bandwidth mode. In serializer mode, a packet will get enqueued
2484  * when a thread cannot enter SRS exclusively. In bandwidth mode,
2485  * packets gets queued if allowed byte-count limit for a tick is
2486  * exceeded. The action that gets taken when MAC_DROP_ON_NO_DESC and
2487  * MAC_TX_NO_ENQUEUE is set is different than when operaing in either
2488  * the default mode or fanout mode. Here packets get dropped or
2489  * returned back to the caller only after hi-watermark worth of data
2490  * is queued.
2491  */
2492 static mac_tx_cookie_t
2493 mac_tx_srs_enqueue(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2494     uint16_t flag, uintptr_t fanout_hint, mblk_t **ret_mp)
2495 {
2496 	mac_tx_cookie_t cookie = NULL;
2497 	int cnt, sz;
2498 	mblk_t *tail;
2499 	boolean_t wakeup_worker = B_TRUE;
2500 
2501 	/*
2502 	 * Ignore fanout hint if we don't have multiple tx rings.
2503 	 */
2504 	if (!TX_MULTI_RING_MODE(mac_srs))
2505 		fanout_hint = 0;
2506 
2507 	if (mac_srs->srs_first != NULL)
2508 		wakeup_worker = B_FALSE;
2509 	MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2510 	if (flag & MAC_DROP_ON_NO_DESC) {
2511 		if (mac_srs->srs_count > mac_srs->srs_tx.st_hiwat) {
2512 			MAC_TX_SRS_DROP_MESSAGE(mac_srs, mp_chain, cookie);
2513 		} else {
2514 			MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2515 			    mp_chain, tail, cnt, sz);
2516 		}
2517 	} else if (flag & MAC_TX_NO_ENQUEUE) {
2518 		if ((mac_srs->srs_count > mac_srs->srs_tx.st_hiwat) ||
2519 		    (mac_srs->srs_state & SRS_TX_WAKEUP_CLIENT)) {
2520 			MAC_TX_SET_NO_ENQUEUE(mac_srs, mp_chain,
2521 			    ret_mp, cookie);
2522 		} else {
2523 			mp_chain->b_prev = (mblk_t *)fanout_hint;
2524 			MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2525 			    mp_chain, tail, cnt, sz);
2526 		}
2527 	} else {
2528 		/*
2529 		 * If you are BW_ENFORCED, just enqueue the
2530 		 * packet. srs_worker will drain it at the
2531 		 * prescribed rate. Before enqueueing, save
2532 		 * the fanout hint.
2533 		 */
2534 		mp_chain->b_prev = (mblk_t *)fanout_hint;
2535 		MAC_TX_SRS_TEST_HIWAT(mac_srs, mp_chain,
2536 		    tail, cnt, sz, cookie);
2537 	}
2538 	if (wakeup_worker)
2539 		cv_signal(&mac_srs->srs_async);
2540 	return (cookie);
2541 }
2542 
2543 /*
2544  * There are five tx modes:
2545  *
2546  * 1) Default mode (SRS_TX_DEFAULT)
2547  * 2) Serialization mode (SRS_TX_SERIALIZE)
2548  * 3) Fanout mode (SRS_TX_FANOUT)
2549  * 4) Bandwdith mode (SRS_TX_BW)
2550  * 5) Fanout and Bandwidth mode (SRS_TX_BW_FANOUT)
2551  *
2552  * The tx mode in which an SRS operates is decided in mac_tx_srs_setup()
2553  * based on the number of Tx rings requested for an SRS and whether
2554  * bandwidth control is requested or not.
2555  *
2556  * In the default mode (i.e., no fanout/no bandwidth), the SRS acts as a
2557  * pass-thru. Packets will go directly to mac_tx_send(). When the underlying
2558  * Tx ring runs out of Tx descs, it starts queueing up packets in SRS.
2559  * When flow-control is relieved, the srs_worker drains the queued
2560  * packets and informs blocked clients to restart sending packets.
2561  *
2562  * In the SRS_TX_SERIALIZE mode, all calls to mac_tx() are serialized.
2563  *
2564  * In the SRS_TX_FANOUT mode, packets will be fanned out to multiple
2565  * Tx rings. Each Tx ring will have a soft ring associated with it.
2566  * These soft rings will be hung off the Tx SRS. Queueing if it happens
2567  * due to lack of Tx desc will be in individual soft ring (and not srs)
2568  * associated with Tx ring.
2569  *
2570  * In the TX_BW mode, tx srs will allow packets to go down to Tx ring
2571  * only if bw is available. Otherwise the packets will be queued in
2572  * SRS. If fanout to multiple Tx rings is configured, the packets will
2573  * be fanned out among the soft rings associated with the Tx rings.
2574  *
2575  * Four flags are used in srs_state for indicating flow control
2576  * conditions : SRS_TX_BLOCKED, SRS_TX_HIWAT, SRS_TX_WAKEUP_CLIENT.
2577  * SRS_TX_BLOCKED indicates out of Tx descs. SRS expects a wakeup from the
2578  * driver below.
2579  * SRS_TX_HIWAT indicates packet count enqueued in Tx SRS exceeded Tx hiwat
2580  * and flow-control pressure is applied back to clients. The clients expect
2581  * wakeup when flow-control is relieved.
2582  * SRS_TX_WAKEUP_CLIENT get set when (flag == MAC_TX_NO_ENQUEUE) and mblk
2583  * got returned back to client either due to lack of Tx descs or due to bw
2584  * control reasons. The clients expect a wakeup when condition is relieved.
2585  *
2586  * The fourth argument to mac_tx() is the flag. Normally it will be 0 but
2587  * some clients set the following values too: MAC_DROP_ON_NO_DESC,
2588  * MAC_TX_NO_ENQUEUE
2589  * Mac clients that do not want packets to be enqueued in the mac layer set
2590  * MAC_DROP_ON_NO_DESC value. The packets won't be queued in the Tx SRS or
2591  * Tx soft rings but instead get dropped when the NIC runs out of desc. The
2592  * behaviour of this flag is different when the Tx is running in serializer
2593  * or bandwidth mode. Under these (Serializer, bandwidth) modes, the packet
2594  * get dropped when Tx high watermark is reached.
2595  * There are some mac clients like vsw, aggr that want the mblks to be
2596  * returned back to clients instead of being queued in Tx SRS (or Tx soft
2597  * rings) under flow-control (i.e., out of desc or exceeding bw limits)
2598  * conditions. These clients call mac_tx() with MAC_TX_NO_ENQUEUE flag set.
2599  * In the default and Tx fanout mode, the un-transmitted mblks will be
2600  * returned back to the clients when the driver runs out of Tx descs.
2601  * SRS_TX_WAKEUP_CLIENT (or S_RING_WAKEUP_CLIENT) will be set in SRS (or
2602  * soft ring) so that the clients can be woken up when Tx desc become
2603  * available. When running in serializer or bandwidth mode mode,
2604  * SRS_TX_WAKEUP_CLIENT will be set when tx hi-watermark is reached.
2605  */
2606 
2607 mac_tx_func_t
2608 mac_tx_get_func(uint32_t mode)
2609 {
2610 	return (mac_tx_mode_list[mode].mac_tx_func);
2611 }
2612 
2613 /* ARGSUSED */
2614 static mac_tx_cookie_t
2615 mac_tx_single_ring_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2616     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2617 {
2618 	mac_srs_tx_t		*srs_tx = &mac_srs->srs_tx;
2619 	boolean_t		is_subflow;
2620 	mac_tx_stats_t		stats;
2621 	mac_tx_cookie_t		cookie = NULL;
2622 
2623 	ASSERT(srs_tx->st_mode == SRS_TX_DEFAULT);
2624 
2625 	/* Regular case with a single Tx ring */
2626 	/*
2627 	 * SRS_TX_BLOCKED is set when underlying NIC runs
2628 	 * out of Tx descs and messages start getting
2629 	 * queued. It won't get reset until
2630 	 * tx_srs_drain() completely drains out the
2631 	 * messages.
2632 	 */
2633 	if ((mac_srs->srs_state & SRS_ENQUEUED) != 0) {
2634 		/* Tx descs/resources not available */
2635 		mutex_enter(&mac_srs->srs_lock);
2636 		if ((mac_srs->srs_state & SRS_ENQUEUED) != 0) {
2637 			cookie = mac_tx_srs_no_desc(mac_srs, mp_chain,
2638 			    flag, ret_mp);
2639 			mutex_exit(&mac_srs->srs_lock);
2640 			return (cookie);
2641 		}
2642 		/*
2643 		 * While we were computing mblk count, the
2644 		 * flow control condition got relieved.
2645 		 * Continue with the transmission.
2646 		 */
2647 		mutex_exit(&mac_srs->srs_lock);
2648 	}
2649 
2650 	is_subflow = ((mac_srs->srs_type & SRST_FLOW) != 0);
2651 
2652 	mp_chain = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
2653 	    mp_chain, (is_subflow ? &stats : NULL));
2654 
2655 	/*
2656 	 * Multiple threads could be here sending packets.
2657 	 * Under such conditions, it is not possible to
2658 	 * automically set SRS_TX_BLOCKED bit to indicate
2659 	 * out of tx desc condition. To atomically set
2660 	 * this, we queue the returned packet and do
2661 	 * the setting of SRS_TX_BLOCKED in
2662 	 * mac_tx_srs_drain().
2663 	 */
2664 	if (mp_chain != NULL) {
2665 		mutex_enter(&mac_srs->srs_lock);
2666 		cookie = mac_tx_srs_no_desc(mac_srs, mp_chain, flag, ret_mp);
2667 		mutex_exit(&mac_srs->srs_lock);
2668 		return (cookie);
2669 	}
2670 
2671 	if (is_subflow)
2672 		FLOW_TX_STATS_UPDATE(mac_srs->srs_flent, &stats);
2673 
2674 	return (NULL);
2675 }
2676 
2677 /*
2678  * mac_tx_serialize_mode
2679  *
2680  * This is an experimental mode implemented as per the request of PAE.
2681  * In this mode, all callers attempting to send a packet to the NIC
2682  * will get serialized. Only one thread at any time will access the
2683  * NIC to send the packet out.
2684  */
2685 /* ARGSUSED */
2686 static mac_tx_cookie_t
2687 mac_tx_serializer_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2688     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2689 {
2690 	boolean_t		is_subflow;
2691 	mac_tx_stats_t		stats;
2692 	mac_tx_cookie_t		cookie = NULL;
2693 	mac_srs_tx_t		*srs_tx = &mac_srs->srs_tx;
2694 
2695 	/* Single ring, serialize below */
2696 	ASSERT(srs_tx->st_mode == SRS_TX_SERIALIZE);
2697 	mutex_enter(&mac_srs->srs_lock);
2698 	if ((mac_srs->srs_first != NULL) ||
2699 	    (mac_srs->srs_state & SRS_PROC)) {
2700 		/*
2701 		 * In serialization mode, queue all packets until
2702 		 * TX_HIWAT is set.
2703 		 * If drop bit is set, drop if TX_HIWAT is set.
2704 		 * If no_enqueue is set, still enqueue until hiwat
2705 		 * is set and return mblks after TX_HIWAT is set.
2706 		 */
2707 		cookie = mac_tx_srs_enqueue(mac_srs, mp_chain,
2708 		    flag, NULL, ret_mp);
2709 		mutex_exit(&mac_srs->srs_lock);
2710 		return (cookie);
2711 	}
2712 	/*
2713 	 * No packets queued, nothing on proc and no flow
2714 	 * control condition. Fast-path, ok. Do inline
2715 	 * processing.
2716 	 */
2717 	mac_srs->srs_state |= SRS_PROC;
2718 	mutex_exit(&mac_srs->srs_lock);
2719 
2720 	is_subflow = ((mac_srs->srs_type & SRST_FLOW) != 0);
2721 
2722 	mp_chain = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
2723 	    mp_chain, (is_subflow ? &stats : NULL));
2724 
2725 	mutex_enter(&mac_srs->srs_lock);
2726 	mac_srs->srs_state &= ~SRS_PROC;
2727 	if (mp_chain != NULL) {
2728 		cookie = mac_tx_srs_enqueue(mac_srs,
2729 		    mp_chain, flag, NULL, ret_mp);
2730 	}
2731 	if (mac_srs->srs_first != NULL) {
2732 		/*
2733 		 * We processed inline our packet and a new
2734 		 * packet/s got queued while we were
2735 		 * processing. Wakeup srs worker
2736 		 */
2737 		cv_signal(&mac_srs->srs_async);
2738 	}
2739 	mutex_exit(&mac_srs->srs_lock);
2740 
2741 	if (is_subflow && cookie == NULL)
2742 		FLOW_TX_STATS_UPDATE(mac_srs->srs_flent, &stats);
2743 
2744 	return (cookie);
2745 }
2746 
2747 /*
2748  * mac_tx_fanout_mode
2749  *
2750  * In this mode, the SRS will have access to multiple Tx rings to send
2751  * the packet out. The fanout hint that is passed as an argument is
2752  * used to find an appropriate ring to fanout the traffic. Each Tx
2753  * ring, in turn,  will have a soft ring associated with it. If a Tx
2754  * ring runs out of Tx desc's the returned packet will be queued in
2755  * the soft ring associated with that Tx ring. The srs itself will not
2756  * queue any packets.
2757  */
2758 
2759 #define	MAC_TX_SOFT_RING_PROCESS(chain) {		       		\
2760 	index = COMPUTE_INDEX(hash, mac_srs->srs_oth_ring_count),	\
2761 	softring = mac_srs->srs_oth_soft_rings[index];			\
2762 	cookie = mac_tx_soft_ring_process(softring, chain, flag, ret_mp); \
2763 	DTRACE_PROBE2(tx__fanout, uint64_t, hash, uint_t, index);	\
2764 }
2765 
2766 static mac_tx_cookie_t
2767 mac_tx_fanout_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2768     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2769 {
2770 	mac_soft_ring_t		*softring;
2771 	uint64_t		hash;
2772 	uint_t			index;
2773 	mac_tx_cookie_t		cookie = NULL;
2774 
2775 	ASSERT(mac_srs->srs_tx.st_mode == SRS_TX_FANOUT);
2776 	if (fanout_hint != 0) {
2777 		/*
2778 		 * The hint is specified by the caller, simply pass the
2779 		 * whole chain to the soft ring.
2780 		 */
2781 		hash = HASH_HINT(fanout_hint);
2782 		MAC_TX_SOFT_RING_PROCESS(mp_chain);
2783 	} else {
2784 		mblk_t *last_mp, *cur_mp, *sub_chain;
2785 		uint64_t last_hash = 0;
2786 		uint_t media = mac_srs->srs_mcip->mci_mip->mi_info.mi_media;
2787 
2788 		/*
2789 		 * Compute the hash from the contents (headers) of the
2790 		 * packets of the mblk chain. Split the chains into
2791 		 * subchains of the same conversation.
2792 		 *
2793 		 * Since there may be more than one ring used for
2794 		 * sub-chains of the same call, and since the caller
2795 		 * does not maintain per conversation state since it
2796 		 * passed a zero hint, unsent subchains will be
2797 		 * dropped.
2798 		 */
2799 
2800 		flag |= MAC_DROP_ON_NO_DESC;
2801 		ret_mp = NULL;
2802 
2803 		ASSERT(ret_mp == NULL);
2804 
2805 		sub_chain = NULL;
2806 		last_mp = NULL;
2807 
2808 		for (cur_mp = mp_chain; cur_mp != NULL;
2809 		    cur_mp = cur_mp->b_next) {
2810 			hash = mac_pkt_hash(media, cur_mp, MAC_PKT_HASH_L4,
2811 			    B_TRUE);
2812 			if (last_hash != 0 && hash != last_hash) {
2813 				/*
2814 				 * Starting a different subchain, send current
2815 				 * chain out.
2816 				 */
2817 				ASSERT(last_mp != NULL);
2818 				last_mp->b_next = NULL;
2819 				MAC_TX_SOFT_RING_PROCESS(sub_chain);
2820 				sub_chain = NULL;
2821 			}
2822 
2823 			/* add packet to subchain */
2824 			if (sub_chain == NULL)
2825 				sub_chain = cur_mp;
2826 			last_mp = cur_mp;
2827 			last_hash = hash;
2828 		}
2829 
2830 		if (sub_chain != NULL) {
2831 			/* send last subchain */
2832 			ASSERT(last_mp != NULL);
2833 			last_mp->b_next = NULL;
2834 			MAC_TX_SOFT_RING_PROCESS(sub_chain);
2835 		}
2836 
2837 		cookie = NULL;
2838 	}
2839 
2840 	return (cookie);
2841 }
2842 
2843 /*
2844  * mac_tx_bw_mode
2845  *
2846  * In the bandwidth mode, Tx srs will allow packets to go down to Tx ring
2847  * only if bw is available. Otherwise the packets will be queued in
2848  * SRS. If the SRS has multiple Tx rings, then packets will get fanned
2849  * out to a Tx rings.
2850  */
2851 static mac_tx_cookie_t
2852 mac_tx_bw_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2853     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2854 {
2855 	int			cnt, sz;
2856 	mblk_t			*tail;
2857 	mac_tx_cookie_t		cookie = NULL;
2858 	mac_srs_tx_t		*srs_tx = &mac_srs->srs_tx;
2859 
2860 	ASSERT(TX_BANDWIDTH_MODE(mac_srs));
2861 	ASSERT(mac_srs->srs_type & SRST_BW_CONTROL);
2862 	mutex_enter(&mac_srs->srs_lock);
2863 	if (mac_srs->srs_bw->mac_bw_limit == 0) {
2864 		/*
2865 		 * zero bandwidth, no traffic is sent: drop the packets,
2866 		 * or return the whole chain if the caller requests all
2867 		 * unsent packets back.
2868 		 */
2869 		if (flag & MAC_TX_NO_ENQUEUE) {
2870 			cookie = (mac_tx_cookie_t)mac_srs;
2871 			*ret_mp = mp_chain;
2872 		} else {
2873 			MAC_TX_SRS_DROP_MESSAGE(mac_srs, mp_chain, cookie);
2874 		}
2875 		mutex_exit(&mac_srs->srs_lock);
2876 		return (cookie);
2877 	} else if ((mac_srs->srs_first != NULL) ||
2878 	    (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)) {
2879 		cookie = mac_tx_srs_enqueue(mac_srs, mp_chain, flag,
2880 		    fanout_hint, ret_mp);
2881 		mutex_exit(&mac_srs->srs_lock);
2882 		return (cookie);
2883 	}
2884 	MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2885 	if (mac_srs->srs_bw->mac_bw_curr_time != lbolt) {
2886 		mac_srs->srs_bw->mac_bw_curr_time = lbolt;
2887 		mac_srs->srs_bw->mac_bw_used = 0;
2888 	} else if (mac_srs->srs_bw->mac_bw_used >
2889 	    mac_srs->srs_bw->mac_bw_limit) {
2890 		mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
2891 		MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2892 		    mp_chain, tail, cnt, sz);
2893 		/*
2894 		 * Wakeup worker thread. Note that worker
2895 		 * thread has to be woken up so that it
2896 		 * can fire up the timer to be woken up
2897 		 * on the next tick. Also once
2898 		 * BW_ENFORCED is set, it can only be
2899 		 * reset by srs_worker thread. Until then
2900 		 * all packets will get queued up in SRS
2901 		 * and hence this this code path won't be
2902 		 * entered until BW_ENFORCED is reset.
2903 		 */
2904 		cv_signal(&mac_srs->srs_async);
2905 		mutex_exit(&mac_srs->srs_lock);
2906 		return (cookie);
2907 	}
2908 
2909 	mac_srs->srs_bw->mac_bw_used += sz;
2910 	mutex_exit(&mac_srs->srs_lock);
2911 
2912 	if (srs_tx->st_mode == SRS_TX_BW_FANOUT) {
2913 		mac_soft_ring_t *softring;
2914 		uint_t indx, hash;
2915 
2916 		hash = HASH_HINT(fanout_hint);
2917 		indx = COMPUTE_INDEX(hash,
2918 		    mac_srs->srs_oth_ring_count);
2919 		softring = mac_srs->srs_oth_soft_rings[indx];
2920 		return (mac_tx_soft_ring_process(softring, mp_chain, flag,
2921 		    ret_mp));
2922 	} else {
2923 		boolean_t		is_subflow;
2924 		mac_tx_stats_t		stats;
2925 
2926 		is_subflow = ((mac_srs->srs_type & SRST_FLOW) != 0);
2927 
2928 		mp_chain = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
2929 		    mp_chain, (is_subflow ? &stats : NULL));
2930 
2931 		if (mp_chain != NULL) {
2932 			mutex_enter(&mac_srs->srs_lock);
2933 			MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2934 			if (mac_srs->srs_bw->mac_bw_used > sz)
2935 				mac_srs->srs_bw->mac_bw_used -= sz;
2936 			else
2937 				mac_srs->srs_bw->mac_bw_used = 0;
2938 			cookie = mac_tx_srs_enqueue(mac_srs, mp_chain, flag,
2939 			    fanout_hint, ret_mp);
2940 			mutex_exit(&mac_srs->srs_lock);
2941 			return (cookie);
2942 		}
2943 		if (is_subflow)
2944 			FLOW_TX_STATS_UPDATE(mac_srs->srs_flent, &stats);
2945 
2946 		return (NULL);
2947 	}
2948 }
2949 
2950 /* ARGSUSED */
2951 void
2952 mac_tx_srs_drain(mac_soft_ring_set_t *mac_srs, uint_t proc_type)
2953 {
2954 	mblk_t			*head, *tail;
2955 	size_t			sz;
2956 	uint32_t		tx_mode;
2957 	uint_t			saved_pkt_count;
2958 	boolean_t		is_subflow;
2959 	mac_tx_stats_t		stats;
2960 	mac_srs_tx_t		*srs_tx = &mac_srs->srs_tx;
2961 
2962 	saved_pkt_count = 0;
2963 	ASSERT(mutex_owned(&mac_srs->srs_lock));
2964 	ASSERT(!(mac_srs->srs_state & SRS_PROC));
2965 
2966 	mac_srs->srs_state |= SRS_PROC;
2967 
2968 	is_subflow = ((mac_srs->srs_type & SRST_FLOW) != 0);
2969 	tx_mode = srs_tx->st_mode;
2970 	if (tx_mode == SRS_TX_DEFAULT || tx_mode == SRS_TX_SERIALIZE) {
2971 		if (mac_srs->srs_first != NULL) {
2972 			head = mac_srs->srs_first;
2973 			tail = mac_srs->srs_last;
2974 			saved_pkt_count = mac_srs->srs_count;
2975 			mac_srs->srs_first = NULL;
2976 			mac_srs->srs_last = NULL;
2977 			mac_srs->srs_count = 0;
2978 			mutex_exit(&mac_srs->srs_lock);
2979 
2980 			head = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
2981 			    head, &stats);
2982 
2983 			mutex_enter(&mac_srs->srs_lock);
2984 			if (head != NULL) {
2985 				/* Device out of tx desc, set block */
2986 				if (head->b_next == NULL)
2987 					VERIFY(head == tail);
2988 				tail->b_next = mac_srs->srs_first;
2989 				mac_srs->srs_first = head;
2990 				mac_srs->srs_count +=
2991 				    (saved_pkt_count - stats.ts_opackets);
2992 				if (mac_srs->srs_last == NULL)
2993 					mac_srs->srs_last = tail;
2994 				MAC_TX_SRS_BLOCK(mac_srs, head);
2995 			} else {
2996 				srs_tx->st_woken_up = B_FALSE;
2997 				if (is_subflow) {
2998 					FLOW_TX_STATS_UPDATE(
2999 					    mac_srs->srs_flent, &stats);
3000 				}
3001 			}
3002 		}
3003 	} else if (tx_mode == SRS_TX_BW) {
3004 		/*
3005 		 * We are here because the timer fired and we have some data
3006 		 * to tranmit. Also mac_tx_srs_worker should have reset
3007 		 * SRS_BW_ENFORCED flag
3008 		 */
3009 		ASSERT(!(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED));
3010 		head = tail = mac_srs->srs_first;
3011 		while (mac_srs->srs_first != NULL) {
3012 			tail = mac_srs->srs_first;
3013 			tail->b_prev = NULL;
3014 			mac_srs->srs_first = tail->b_next;
3015 			if (mac_srs->srs_first == NULL)
3016 				mac_srs->srs_last = NULL;
3017 			mac_srs->srs_count--;
3018 			sz = msgdsize(tail);
3019 			mac_srs->srs_size -= sz;
3020 			saved_pkt_count++;
3021 			MAC_TX_UPDATE_BW_INFO(mac_srs, sz);
3022 
3023 			if (mac_srs->srs_bw->mac_bw_used <
3024 			    mac_srs->srs_bw->mac_bw_limit)
3025 				continue;
3026 
3027 			if (mac_srs->srs_bw->mac_bw_curr_time != lbolt) {
3028 				mac_srs->srs_bw->mac_bw_curr_time = lbolt;
3029 				mac_srs->srs_bw->mac_bw_used = sz;
3030 				continue;
3031 			}
3032 			mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
3033 			break;
3034 		}
3035 
3036 		ASSERT((head == NULL && tail == NULL) ||
3037 		    (head != NULL && tail != NULL));
3038 		if (tail != NULL) {
3039 			tail->b_next = NULL;
3040 			mutex_exit(&mac_srs->srs_lock);
3041 
3042 			head = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
3043 			    head, &stats);
3044 
3045 			mutex_enter(&mac_srs->srs_lock);
3046 			if (head != NULL) {
3047 				uint_t size_sent;
3048 
3049 				/* Device out of tx desc, set block */
3050 				if (head->b_next == NULL)
3051 					VERIFY(head == tail);
3052 				tail->b_next = mac_srs->srs_first;
3053 				mac_srs->srs_first = head;
3054 				mac_srs->srs_count +=
3055 				    (saved_pkt_count - stats.ts_opackets);
3056 				if (mac_srs->srs_last == NULL)
3057 					mac_srs->srs_last = tail;
3058 				size_sent = sz - stats.ts_obytes;
3059 				mac_srs->srs_size += size_sent;
3060 				mac_srs->srs_bw->mac_bw_sz += size_sent;
3061 				if (mac_srs->srs_bw->mac_bw_used > size_sent) {
3062 					mac_srs->srs_bw->mac_bw_used -=
3063 					    size_sent;
3064 				} else {
3065 					mac_srs->srs_bw->mac_bw_used = 0;
3066 				}
3067 				MAC_TX_SRS_BLOCK(mac_srs, head);
3068 			} else {
3069 				srs_tx->st_woken_up = B_FALSE;
3070 				if (is_subflow) {
3071 					FLOW_TX_STATS_UPDATE(
3072 					    mac_srs->srs_flent, &stats);
3073 				}
3074 			}
3075 		}
3076 	} else if (tx_mode == SRS_TX_BW_FANOUT) {
3077 		mblk_t *prev;
3078 		mac_soft_ring_t *softring;
3079 		uint64_t hint;
3080 
3081 		/*
3082 		 * We are here because the timer fired and we
3083 		 * have some quota to tranmit.
3084 		 */
3085 		prev = NULL;
3086 		head = tail = mac_srs->srs_first;
3087 		while (mac_srs->srs_first != NULL) {
3088 			tail = mac_srs->srs_first;
3089 			mac_srs->srs_first = tail->b_next;
3090 			if (mac_srs->srs_first == NULL)
3091 				mac_srs->srs_last = NULL;
3092 			mac_srs->srs_count--;
3093 			sz = msgdsize(tail);
3094 			mac_srs->srs_size -= sz;
3095 			mac_srs->srs_bw->mac_bw_used += sz;
3096 			if (prev == NULL)
3097 				hint = (ulong_t)tail->b_prev;
3098 			if (hint != (ulong_t)tail->b_prev) {
3099 				prev->b_next = NULL;
3100 				mutex_exit(&mac_srs->srs_lock);
3101 				TX_SRS_TO_SOFT_RING(mac_srs, head, hint);
3102 				head = tail;
3103 				hint = (ulong_t)tail->b_prev;
3104 				mutex_enter(&mac_srs->srs_lock);
3105 			}
3106 
3107 			prev = tail;
3108 			tail->b_prev = NULL;
3109 			if (mac_srs->srs_bw->mac_bw_used <
3110 			    mac_srs->srs_bw->mac_bw_limit)
3111 				continue;
3112 
3113 			if (mac_srs->srs_bw->mac_bw_curr_time != lbolt) {
3114 				mac_srs->srs_bw->mac_bw_curr_time = lbolt;
3115 				mac_srs->srs_bw->mac_bw_used = 0;
3116 				continue;
3117 			}
3118 			mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
3119 			break;
3120 		}
3121 		ASSERT((head == NULL && tail == NULL) ||
3122 		    (head != NULL && tail != NULL));
3123 		if (tail != NULL) {
3124 			tail->b_next = NULL;
3125 			mutex_exit(&mac_srs->srs_lock);
3126 			TX_SRS_TO_SOFT_RING(mac_srs, head, hint);
3127 			mutex_enter(&mac_srs->srs_lock);
3128 		}
3129 	}
3130 	/*
3131 	 * SRS_TX_FANOUT case not considered here because packets
3132 	 * won't be queued in the SRS for this case. Packets will
3133 	 * be sent directly to soft rings underneath and if there
3134 	 * is any queueing at all, it would be in Tx side soft
3135 	 * rings.
3136 	 */
3137 
3138 	/*
3139 	 * When srs_count becomes 0, reset SRS_TX_HIWAT and
3140 	 * SRS_TX_WAKEUP_CLIENT and wakeup registered clients.
3141 	 */
3142 	if (mac_srs->srs_count == 0 && (mac_srs->srs_state &
3143 	    (SRS_TX_HIWAT | SRS_TX_WAKEUP_CLIENT | SRS_ENQUEUED))) {
3144 		mac_tx_notify_cb_t *mtnfp;
3145 		mac_cb_t *mcb;
3146 		mac_client_impl_t *mcip = mac_srs->srs_mcip;
3147 		boolean_t wakeup_required = B_FALSE;
3148 
3149 		if (mac_srs->srs_state &
3150 		    (SRS_TX_HIWAT|SRS_TX_WAKEUP_CLIENT)) {
3151 			wakeup_required = B_TRUE;
3152 		}
3153 		mac_srs->srs_state &= ~(SRS_TX_HIWAT |
3154 		    SRS_TX_WAKEUP_CLIENT | SRS_ENQUEUED);
3155 		mutex_exit(&mac_srs->srs_lock);
3156 		if (wakeup_required) {
3157 			/* Wakeup callback registered clients */
3158 			MAC_CALLBACK_WALKER_INC(&mcip->mci_tx_notify_cb_info);
3159 			for (mcb = mcip->mci_tx_notify_cb_list; mcb != NULL;
3160 			    mcb = mcb->mcb_nextp) {
3161 				mtnfp = (mac_tx_notify_cb_t *)mcb->mcb_objp;
3162 				mtnfp->mtnf_fn(mtnfp->mtnf_arg,
3163 				    (mac_tx_cookie_t)mac_srs);
3164 			}
3165 			MAC_CALLBACK_WALKER_DCR(&mcip->mci_tx_notify_cb_info,
3166 			    &mcip->mci_tx_notify_cb_list);
3167 			/*
3168 			 * If the client is not the primary MAC client, then we
3169 			 * need to send the notification to the clients upper
3170 			 * MAC, i.e. mci_upper_mip.
3171 			 */
3172 			mac_tx_notify(mcip->mci_upper_mip != NULL ?
3173 			    mcip->mci_upper_mip : mcip->mci_mip);
3174 		}
3175 		mutex_enter(&mac_srs->srs_lock);
3176 	}
3177 	mac_srs->srs_state &= ~SRS_PROC;
3178 }
3179 
3180 /*
3181  * Given a packet, get the flow_entry that identifies the flow
3182  * to which that packet belongs. The flow_entry will contain
3183  * the transmit function to be used to send the packet. If the
3184  * function returns NULL, the packet should be sent using the
3185  * underlying NIC.
3186  */
3187 static flow_entry_t *
3188 mac_tx_classify(mac_impl_t *mip, mblk_t *mp)
3189 {
3190 	flow_entry_t		*flent = NULL;
3191 	mac_client_impl_t	*mcip;
3192 	int	err;
3193 
3194 	/*
3195 	 * Do classification on the packet.
3196 	 */
3197 	err = mac_flow_lookup(mip->mi_flow_tab, mp, FLOW_OUTBOUND, &flent);
3198 	if (err != 0)
3199 		return (NULL);
3200 
3201 	/*
3202 	 * This flent might just be an additional one on the MAC client,
3203 	 * i.e. for classification purposes (different fdesc), however
3204 	 * the resources, SRS et. al., are in the mci_flent, so if
3205 	 * this isn't the mci_flent, we need to get it.
3206 	 */
3207 	if ((mcip = flent->fe_mcip) != NULL && mcip->mci_flent != flent) {
3208 		FLOW_REFRELE(flent);
3209 		flent = mcip->mci_flent;
3210 		FLOW_TRY_REFHOLD(flent, err);
3211 		if (err != 0)
3212 			return (NULL);
3213 	}
3214 
3215 	return (flent);
3216 }
3217 
3218 /*
3219  * This macro is only meant to be used by mac_tx_send().
3220  */
3221 #define	CHECK_VID_AND_ADD_TAG(mp) {			\
3222 	if (vid_check) {				\
3223 		int err = 0;				\
3224 							\
3225 		MAC_VID_CHECK(src_mcip, (mp), err);	\
3226 		if (err != 0) {				\
3227 			freemsg((mp));			\
3228 			(mp) = next;			\
3229 			oerrors++;			\
3230 			continue;			\
3231 		}					\
3232 	}						\
3233 	if (add_tag) {					\
3234 		(mp) = mac_add_vlan_tag((mp), 0, vid);	\
3235 		if ((mp) == NULL) {			\
3236 			(mp) = next;			\
3237 			oerrors++;			\
3238 			continue;			\
3239 		}					\
3240 	}						\
3241 }
3242 
3243 mblk_t *
3244 mac_tx_send(mac_client_handle_t mch, mac_ring_handle_t ring, mblk_t *mp_chain,
3245     mac_tx_stats_t *stats)
3246 {
3247 	mac_client_impl_t *src_mcip = (mac_client_impl_t *)mch;
3248 	mac_impl_t *mip = src_mcip->mci_mip;
3249 	uint_t obytes = 0, opackets = 0, oerrors = 0;
3250 	mblk_t *mp = NULL, *next;
3251 	boolean_t vid_check, add_tag;
3252 	uint16_t vid = 0;
3253 
3254 	if (mip->mi_nclients > 1) {
3255 		vid_check = MAC_VID_CHECK_NEEDED(src_mcip);
3256 		add_tag = MAC_TAG_NEEDED(src_mcip);
3257 		if (add_tag)
3258 			vid = mac_client_vid(mch);
3259 	} else {
3260 		ASSERT(mip->mi_nclients == 1);
3261 		vid_check = add_tag = B_FALSE;
3262 	}
3263 
3264 	/*
3265 	 * Fastpath: if there's only one client, and there's no
3266 	 * multicast listeners, we simply send the packet down to the
3267 	 * underlying NIC.
3268 	 */
3269 	if (mip->mi_nactiveclients == 1 && mip->mi_promisc_list == NULL)  {
3270 		DTRACE_PROBE2(fastpath,
3271 		    mac_client_impl_t *, src_mcip, mblk_t *, mp_chain);
3272 
3273 		mp = mp_chain;
3274 		while (mp != NULL) {
3275 			next = mp->b_next;
3276 			mp->b_next = NULL;
3277 			opackets++;
3278 			obytes += (mp->b_cont == NULL ? MBLKL(mp) :
3279 			    msgdsize(mp));
3280 
3281 			CHECK_VID_AND_ADD_TAG(mp);
3282 			MAC_TX(mip, ring, mp,
3283 			    ((src_mcip->mci_state_flags & MCIS_SHARE_BOUND) !=
3284 			    0));
3285 
3286 			/*
3287 			 * If the driver is out of descriptors and does a
3288 			 * partial send it will return a chain of unsent
3289 			 * mblks. Adjust the accounting stats.
3290 			 */
3291 			if (mp != NULL) {
3292 				opackets--;
3293 				obytes -= msgdsize(mp);
3294 				mp->b_next = next;
3295 				break;
3296 			}
3297 			mp = next;
3298 		}
3299 		goto done;
3300 	}
3301 
3302 	/*
3303 	 * No fastpath, we either have more than one MAC client
3304 	 * defined on top of the same MAC, or one or more MAC
3305 	 * client promiscuous callbacks.
3306 	 */
3307 	DTRACE_PROBE3(slowpath, mac_client_impl_t *,
3308 	    src_mcip, int, mip->mi_nclients, mblk_t *, mp_chain);
3309 
3310 	mp = mp_chain;
3311 	while (mp != NULL) {
3312 		flow_entry_t *dst_flow_ent;
3313 		void *flow_cookie;
3314 		size_t	pkt_size;
3315 		mblk_t *mp1;
3316 
3317 		next = mp->b_next;
3318 		mp->b_next = NULL;
3319 		opackets++;
3320 		pkt_size = (mp->b_cont == NULL ? MBLKL(mp) : msgdsize(mp));
3321 		obytes += pkt_size;
3322 		CHECK_VID_AND_ADD_TAG(mp);
3323 
3324 		/*
3325 		 * Check if there are promiscuous mode callbacks defined.
3326 		 */
3327 		if (mip->mi_promisc_list != NULL)
3328 			mac_promisc_dispatch(mip, mp, src_mcip);
3329 
3330 		/*
3331 		 * Find the destination.
3332 		 */
3333 		dst_flow_ent = mac_tx_classify(mip, mp);
3334 
3335 		if (dst_flow_ent != NULL) {
3336 			size_t	hdrsize;
3337 			int	err = 0;
3338 
3339 			if (mip->mi_info.mi_nativemedia == DL_ETHER) {
3340 				struct ether_vlan_header *evhp =
3341 				    (struct ether_vlan_header *)mp->b_rptr;
3342 
3343 				if (ntohs(evhp->ether_tpid) == ETHERTYPE_VLAN)
3344 					hdrsize = sizeof (*evhp);
3345 				else
3346 					hdrsize = sizeof (struct ether_header);
3347 			} else {
3348 				mac_header_info_t	mhi;
3349 
3350 				err = mac_header_info((mac_handle_t)mip,
3351 				    mp, &mhi);
3352 				if (err == 0)
3353 					hdrsize = mhi.mhi_hdrsize;
3354 			}
3355 
3356 			/*
3357 			 * Got a matching flow. It's either another
3358 			 * MAC client, or a broadcast/multicast flow.
3359 			 * Make sure the packet size is within the
3360 			 * allowed size. If not drop the packet and
3361 			 * move to next packet.
3362 			 */
3363 			if (err != 0 ||
3364 			    (pkt_size - hdrsize) > mip->mi_sdu_max) {
3365 				oerrors++;
3366 				DTRACE_PROBE2(loopback__drop, size_t, pkt_size,
3367 				    mblk_t *, mp);
3368 				freemsg(mp);
3369 				mp = next;
3370 				FLOW_REFRELE(dst_flow_ent);
3371 				continue;
3372 			}
3373 			flow_cookie = mac_flow_get_client_cookie(dst_flow_ent);
3374 			if (flow_cookie != NULL) {
3375 				/*
3376 				 * The vnic_bcast_send function expects
3377 				 * to receive the sender MAC client
3378 				 * as value for arg2.
3379 				 */
3380 				mac_bcast_send(flow_cookie, src_mcip, mp,
3381 				    B_TRUE);
3382 			} else {
3383 				/*
3384 				 * loopback the packet to a
3385 				 * local MAC client. We force a context
3386 				 * switch if both source and destination
3387 				 * MAC clients are used by IP, i.e. bypass
3388 				 * is set.
3389 				 */
3390 				boolean_t do_switch;
3391 				mac_client_impl_t *dst_mcip =
3392 				    dst_flow_ent->fe_mcip;
3393 
3394 				do_switch = ((src_mcip->mci_state_flags &
3395 				    dst_mcip->mci_state_flags &
3396 				    MCIS_CLIENT_POLL_CAPABLE) != 0);
3397 
3398 				if ((mp1 = mac_fix_cksum(mp)) != NULL) {
3399 					(dst_flow_ent->fe_cb_fn)(
3400 					    dst_flow_ent->fe_cb_arg1,
3401 					    dst_flow_ent->fe_cb_arg2,
3402 					    mp1, do_switch);
3403 				}
3404 			}
3405 			FLOW_REFRELE(dst_flow_ent);
3406 		} else {
3407 			/*
3408 			 * Unknown destination, send via the underlying
3409 			 * NIC.
3410 			 */
3411 			MAC_TX(mip, ring, mp,
3412 			    ((src_mcip->mci_state_flags & MCIS_SHARE_BOUND) !=
3413 			    0));
3414 			if (mp != NULL) {
3415 				/*
3416 				 * Adjust for the last packet that
3417 				 * could not be transmitted
3418 				 */
3419 				opackets--;
3420 				obytes -= pkt_size;
3421 				mp->b_next = next;
3422 				break;
3423 			}
3424 		}
3425 		mp = next;
3426 	}
3427 
3428 done:
3429 	src_mcip->mci_stat_obytes += obytes;
3430 	src_mcip->mci_stat_opackets += opackets;
3431 	src_mcip->mci_stat_oerrors += oerrors;
3432 
3433 	if (stats != NULL) {
3434 		stats->ts_opackets = opackets;
3435 		stats->ts_obytes = obytes;
3436 		stats->ts_oerrors = oerrors;
3437 	}
3438 	return (mp);
3439 }
3440 
3441 /*
3442  * mac_tx_srs_ring_present
3443  *
3444  * Returns whether the specified ring is part of the specified SRS.
3445  */
3446 boolean_t
3447 mac_tx_srs_ring_present(mac_soft_ring_set_t *srs, mac_ring_t *tx_ring)
3448 {
3449 	int i;
3450 	mac_soft_ring_t *soft_ring;
3451 
3452 	if (srs->srs_tx.st_arg2 == tx_ring)
3453 		return (B_TRUE);
3454 
3455 	for (i = 0; i < srs->srs_oth_ring_count; i++) {
3456 		soft_ring =  srs->srs_oth_soft_rings[i];
3457 		if (soft_ring->s_ring_tx_arg2 == tx_ring)
3458 			return (B_TRUE);
3459 	}
3460 
3461 	return (B_FALSE);
3462 }
3463 
3464 /*
3465  * mac_tx_srs_wakeup
3466  *
3467  * Called when Tx desc become available. Wakeup the appropriate worker
3468  * thread after resetting the SRS_TX_BLOCKED/S_RING_BLOCK bit in the
3469  * state field.
3470  */
3471 void
3472 mac_tx_srs_wakeup(mac_soft_ring_set_t *mac_srs, mac_ring_handle_t ring)
3473 {
3474 	int i;
3475 	mac_soft_ring_t *sringp;
3476 	mac_srs_tx_t *srs_tx = &mac_srs->srs_tx;
3477 
3478 	mutex_enter(&mac_srs->srs_lock);
3479 	if (TX_SINGLE_RING_MODE(mac_srs)) {
3480 		if (srs_tx->st_arg2 == ring &&
3481 		    mac_srs->srs_state & SRS_TX_BLOCKED) {
3482 			mac_srs->srs_state &= ~SRS_TX_BLOCKED;
3483 			srs_tx->st_unblocked_cnt++;
3484 			cv_signal(&mac_srs->srs_async);
3485 		}
3486 		/*
3487 		 * A wakeup can come before tx_srs_drain() could
3488 		 * grab srs lock and set SRS_TX_BLOCKED. So
3489 		 * always set woken_up flag when we come here.
3490 		 */
3491 		srs_tx->st_woken_up = B_TRUE;
3492 		mutex_exit(&mac_srs->srs_lock);
3493 		return;
3494 	}
3495 
3496 	/* If you are here, it is for FANOUT or BW_FANOUT case */
3497 	ASSERT(TX_MULTI_RING_MODE(mac_srs));
3498 	for (i = 0; i < mac_srs->srs_oth_ring_count; i++) {
3499 		sringp = mac_srs->srs_oth_soft_rings[i];
3500 		mutex_enter(&sringp->s_ring_lock);
3501 		if (sringp->s_ring_tx_arg2 == ring) {
3502 			if (sringp->s_ring_state & S_RING_BLOCK) {
3503 				sringp->s_ring_state &= ~S_RING_BLOCK;
3504 				sringp->s_ring_unblocked_cnt++;
3505 				cv_signal(&sringp->s_ring_async);
3506 			}
3507 			sringp->s_ring_tx_woken_up = B_TRUE;
3508 		}
3509 		mutex_exit(&sringp->s_ring_lock);
3510 	}
3511 	mutex_exit(&mac_srs->srs_lock);
3512 }
3513 
3514 /*
3515  * Once the driver is done draining, send a MAC_NOTE_TX notification to unleash
3516  * the blocked clients again.
3517  */
3518 void
3519 mac_tx_notify(mac_impl_t *mip)
3520 {
3521 	i_mac_notify(mip, MAC_NOTE_TX);
3522 }
3523 
3524 /*
3525  * RX SOFTRING RELATED FUNCTIONS
3526  *
3527  * These functions really belong in mac_soft_ring.c and here for
3528  * a short period.
3529  */
3530 
3531 #define	SOFT_RING_ENQUEUE_CHAIN(ringp, mp, tail, cnt, sz) {	       	\
3532 	/*								\
3533 	 * Enqueue our mblk chain.					\
3534 	 */								\
3535 	ASSERT(MUTEX_HELD(&(ringp)->s_ring_lock));			\
3536 									\
3537 	if ((ringp)->s_ring_last != NULL)				\
3538 		(ringp)->s_ring_last->b_next = (mp);			\
3539 	else								\
3540 		(ringp)->s_ring_first = (mp);				\
3541 	(ringp)->s_ring_last = (tail);					\
3542 	(ringp)->s_ring_count += (cnt);					\
3543 	ASSERT((ringp)->s_ring_count > 0);				\
3544 	if ((ringp)->s_ring_type & ST_RING_BW_CTL) {			\
3545 		(ringp)->s_ring_size += sz;				\
3546 	}								\
3547 }
3548 
3549 /*
3550  * Default entry point to deliver a packet chain to a MAC client.
3551  * If the MAC client has flows, do the classification with these
3552  * flows as well.
3553  */
3554 /* ARGSUSED */
3555 void
3556 mac_rx_deliver(void *arg1, mac_resource_handle_t mrh, mblk_t *mp_chain,
3557     mac_header_info_t *arg3)
3558 {
3559 	mac_client_impl_t *mcip = arg1;
3560 
3561 	if (mcip->mci_nvids == 1 &&
3562 	    !(mcip->mci_state_flags & MCIS_STRIP_DISABLE)) {
3563 		/*
3564 		 * If the client has exactly one VID associated with it
3565 		 * and striping of VLAN header is not disabled,
3566 		 * remove the VLAN tag from the packet before
3567 		 * passing it on to the client's receive callback.
3568 		 * Note that this needs to be done after we dispatch
3569 		 * the packet to the promiscuous listeners of the
3570 		 * client, since they expect to see the whole
3571 		 * frame including the VLAN headers.
3572 		 */
3573 		mp_chain = mac_strip_vlan_tag_chain(mp_chain);
3574 	}
3575 
3576 	mcip->mci_rx_fn(mcip->mci_rx_arg, mrh, mp_chain, B_FALSE);
3577 }
3578 
3579 /*
3580  * mac_rx_soft_ring_process
3581  *
3582  * process a chain for a given soft ring. The number of packets queued
3583  * in the SRS and its associated soft rings (including this one) is
3584  * very small (tracked by srs_poll_pkt_cnt), then allow the entering
3585  * thread (interrupt or poll thread) to do inline processing. This
3586  * helps keep the latency down under low load.
3587  *
3588  * The proc and arg for each mblk is already stored in the mblk in
3589  * appropriate places.
3590  */
3591 /* ARGSUSED */
3592 void
3593 mac_rx_soft_ring_process(mac_client_impl_t *mcip, mac_soft_ring_t *ringp,
3594     mblk_t *mp_chain, mblk_t *tail, int cnt, size_t sz)
3595 {
3596 	mac_direct_rx_t		proc;
3597 	void			*arg1;
3598 	mac_resource_handle_t	arg2;
3599 	mac_soft_ring_set_t	*mac_srs = ringp->s_ring_set;
3600 
3601 	ASSERT(ringp != NULL);
3602 	ASSERT(mp_chain != NULL);
3603 	ASSERT(tail != NULL);
3604 	ASSERT(MUTEX_NOT_HELD(&ringp->s_ring_lock));
3605 
3606 	mutex_enter(&ringp->s_ring_lock);
3607 	ringp->s_ring_total_inpkt += cnt;
3608 	if ((mac_srs->srs_rx.sr_poll_pkt_cnt <= 1) &&
3609 	    !(ringp->s_ring_type & ST_RING_WORKER_ONLY)) {
3610 		/* If on processor or blanking on, then enqueue and return */
3611 		if (ringp->s_ring_state & S_RING_BLANK ||
3612 		    ringp->s_ring_state & S_RING_PROC) {
3613 			SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);
3614 			mutex_exit(&ringp->s_ring_lock);
3615 			return;
3616 		}
3617 		proc = ringp->s_ring_rx_func;
3618 		arg1 = ringp->s_ring_rx_arg1;
3619 		arg2 = ringp->s_ring_rx_arg2;
3620 		/*
3621 		 * See if anything is already queued. If we are the
3622 		 * first packet, do inline processing else queue the
3623 		 * packet and do the drain.
3624 		 */
3625 		if (ringp->s_ring_first == NULL) {
3626 			/*
3627 			 * Fast-path, ok to process and nothing queued.
3628 			 */
3629 			ringp->s_ring_run = curthread;
3630 			ringp->s_ring_state |= (S_RING_PROC);
3631 
3632 			mutex_exit(&ringp->s_ring_lock);
3633 
3634 			/*
3635 			 * We are the chain of 1 packet so
3636 			 * go through this fast path.
3637 			 */
3638 			ASSERT(mp_chain->b_next == NULL);
3639 
3640 			(*proc)(arg1, arg2, mp_chain, NULL);
3641 
3642 			ASSERT(MUTEX_NOT_HELD(&ringp->s_ring_lock));
3643 			/*
3644 			 * If we have a soft ring set which is doing
3645 			 * bandwidth control, we need to decrement
3646 			 * srs_size and count so it the SRS can have a
3647 			 * accurate idea of what is the real data
3648 			 * queued between SRS and its soft rings. We
3649 			 * decrement the counters only when the packet
3650 			 * gets processed by both SRS and the soft ring.
3651 			 */
3652 			mutex_enter(&mac_srs->srs_lock);
3653 			MAC_UPDATE_SRS_COUNT_LOCKED(mac_srs, cnt);
3654 			MAC_UPDATE_SRS_SIZE_LOCKED(mac_srs, sz);
3655 			mutex_exit(&mac_srs->srs_lock);
3656 
3657 			mutex_enter(&ringp->s_ring_lock);
3658 			ringp->s_ring_run = NULL;
3659 			ringp->s_ring_state &= ~S_RING_PROC;
3660 			if (ringp->s_ring_state & S_RING_CLIENT_WAIT)
3661 				cv_signal(&ringp->s_ring_client_cv);
3662 
3663 			if ((ringp->s_ring_first == NULL) ||
3664 			    (ringp->s_ring_state & S_RING_BLANK)) {
3665 				/*
3666 				 * We processed inline our packet and
3667 				 * nothing new has arrived or our
3668 				 * receiver doesn't want to receive
3669 				 * any packets. We are done.
3670 				 */
3671 				mutex_exit(&ringp->s_ring_lock);
3672 				return;
3673 			}
3674 		} else {
3675 			SOFT_RING_ENQUEUE_CHAIN(ringp,
3676 			    mp_chain, tail, cnt, sz);
3677 		}
3678 
3679 		/*
3680 		 * We are here because either we couldn't do inline
3681 		 * processing (because something was already
3682 		 * queued), or we had a chain of more than one
3683 		 * packet, or something else arrived after we were
3684 		 * done with inline processing.
3685 		 */
3686 		ASSERT(MUTEX_HELD(&ringp->s_ring_lock));
3687 		ASSERT(ringp->s_ring_first != NULL);
3688 
3689 		ringp->s_ring_drain_func(ringp);
3690 		mutex_exit(&ringp->s_ring_lock);
3691 		return;
3692 	} else {
3693 		/* ST_RING_WORKER_ONLY case */
3694 		SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);
3695 		mac_soft_ring_worker_wakeup(ringp);
3696 		mutex_exit(&ringp->s_ring_lock);
3697 	}
3698 }
3699 
3700 /*
3701  * TX SOFTRING RELATED FUNCTIONS
3702  *
3703  * These functions really belong in mac_soft_ring.c and here for
3704  * a short period.
3705  */
3706 
3707 #define	TX_SOFT_RING_ENQUEUE_CHAIN(ringp, mp, tail, cnt, sz) {	       	\
3708 	ASSERT(MUTEX_HELD(&ringp->s_ring_lock));			\
3709 	ringp->s_ring_state |= S_RING_ENQUEUED;				\
3710 	SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);	\
3711 }
3712 
3713 /*
3714  * mac_tx_sring_queued
3715  *
3716  * When we are out of transmit descriptors and we already have a
3717  * queue that exceeds hiwat (or the client called us with
3718  * MAC_TX_NO_ENQUEUE or MAC_DROP_ON_NO_DESC flag), return the
3719  * soft ring pointer as the opaque cookie for the client enable
3720  * flow control.
3721  */
3722 static mac_tx_cookie_t
3723 mac_tx_sring_enqueue(mac_soft_ring_t *ringp, mblk_t *mp_chain, uint16_t flag,
3724     mblk_t **ret_mp)
3725 {
3726 	int cnt;
3727 	size_t sz;
3728 	mblk_t *tail;
3729 	mac_soft_ring_set_t *mac_srs = ringp->s_ring_set;
3730 	mac_tx_cookie_t cookie = NULL;
3731 	boolean_t wakeup_worker = B_TRUE;
3732 
3733 	ASSERT(MUTEX_HELD(&ringp->s_ring_lock));
3734 	MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
3735 	if (flag & MAC_DROP_ON_NO_DESC) {
3736 		mac_pkt_drop(NULL, NULL, mp_chain, B_FALSE);
3737 		/* increment freed stats */
3738 		ringp->s_ring_drops += cnt;
3739 		cookie = (mac_tx_cookie_t)ringp;
3740 	} else {
3741 		if (ringp->s_ring_first != NULL)
3742 			wakeup_worker = B_FALSE;
3743 
3744 		if (flag & MAC_TX_NO_ENQUEUE) {
3745 			/*
3746 			 * If QUEUED is not set, queue the packet
3747 			 * and let mac_tx_soft_ring_drain() set
3748 			 * the TX_BLOCKED bit for the reasons
3749 			 * explained above. Otherwise, return the
3750 			 * mblks.
3751 			 */
3752 			if (wakeup_worker) {
3753 				TX_SOFT_RING_ENQUEUE_CHAIN(ringp,
3754 				    mp_chain, tail, cnt, sz);
3755 			} else {
3756 				ringp->s_ring_state |= S_RING_WAKEUP_CLIENT;
3757 				cookie = (mac_tx_cookie_t)ringp;
3758 				*ret_mp = mp_chain;
3759 			}
3760 		} else {
3761 			boolean_t enqueue = B_TRUE;
3762 
3763 			if (ringp->s_ring_count > ringp->s_ring_tx_hiwat) {
3764 				/*
3765 				 * flow-controlled. Store ringp in cookie
3766 				 * so that it can be returned as
3767 				 * mac_tx_cookie_t to client
3768 				 */
3769 				ringp->s_ring_state |= S_RING_TX_HIWAT;
3770 				cookie = (mac_tx_cookie_t)ringp;
3771 				ringp->s_ring_hiwat_cnt++;
3772 				if (ringp->s_ring_count >
3773 				    ringp->s_ring_tx_max_q_cnt) {
3774 					/* increment freed stats */
3775 					ringp->s_ring_drops += cnt;
3776 					/*
3777 					 * b_prev may be set to the fanout hint
3778 					 * hence can't use freemsg directly
3779 					 */
3780 					mac_pkt_drop(NULL, NULL,
3781 					    mp_chain, B_FALSE);
3782 					DTRACE_PROBE1(tx_queued_hiwat,
3783 					    mac_soft_ring_t *, ringp);
3784 					enqueue = B_FALSE;
3785 				}
3786 			}
3787 			if (enqueue) {
3788 				TX_SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain,
3789 				    tail, cnt, sz);
3790 			}
3791 		}
3792 		if (wakeup_worker)
3793 			cv_signal(&ringp->s_ring_async);
3794 	}
3795 	return (cookie);
3796 }
3797 
3798 
3799 /*
3800  * mac_tx_soft_ring_process
3801  *
3802  * This routine is called when fanning out outgoing traffic among
3803  * multipe Tx rings.
3804  * Note that a soft ring is associated with a h/w Tx ring.
3805  */
3806 mac_tx_cookie_t
3807 mac_tx_soft_ring_process(mac_soft_ring_t *ringp, mblk_t *mp_chain,
3808     uint16_t flag, mblk_t **ret_mp)
3809 {
3810 	mac_soft_ring_set_t *mac_srs = ringp->s_ring_set;
3811 	int	cnt;
3812 	size_t	sz;
3813 	mblk_t	*tail;
3814 	mac_tx_cookie_t cookie = NULL;
3815 
3816 	ASSERT(ringp != NULL);
3817 	ASSERT(mp_chain != NULL);
3818 	ASSERT(MUTEX_NOT_HELD(&ringp->s_ring_lock));
3819 	/*
3820 	 * Only two modes can come here; either it can be
3821 	 * SRS_TX_BW_FANOUT or SRS_TX_FANOUT
3822 	 */
3823 	ASSERT(mac_srs->srs_tx.st_mode == SRS_TX_FANOUT ||
3824 	    mac_srs->srs_tx.st_mode == SRS_TX_BW_FANOUT);
3825 
3826 	if (ringp->s_ring_type & ST_RING_WORKER_ONLY) {
3827 		/* Serialization mode */
3828 
3829 		mutex_enter(&ringp->s_ring_lock);
3830 		if (ringp->s_ring_count > ringp->s_ring_tx_hiwat) {
3831 			cookie = mac_tx_sring_enqueue(ringp, mp_chain,
3832 			    flag, ret_mp);
3833 			mutex_exit(&ringp->s_ring_lock);
3834 			return (cookie);
3835 		}
3836 		MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
3837 		TX_SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);
3838 		if (ringp->s_ring_state & (S_RING_BLOCK | S_RING_PROC)) {
3839 			/*
3840 			 * If ring is blocked due to lack of Tx
3841 			 * descs, just return. Worker thread
3842 			 * will get scheduled when Tx desc's
3843 			 * become available.
3844 			 */
3845 			mutex_exit(&ringp->s_ring_lock);
3846 			return (cookie);
3847 		}
3848 		mac_soft_ring_worker_wakeup(ringp);
3849 		mutex_exit(&ringp->s_ring_lock);
3850 		return (cookie);
3851 	} else {
3852 		/* Default fanout mode */
3853 		/*
3854 		 * S_RING_BLOCKED is set when underlying NIC runs
3855 		 * out of Tx descs and messages start getting
3856 		 * queued. It won't get reset until
3857 		 * tx_srs_drain() completely drains out the
3858 		 * messages.
3859 		 */
3860 		boolean_t		is_subflow;
3861 		mac_tx_stats_t		stats;
3862 
3863 		if (ringp->s_ring_state & S_RING_ENQUEUED) {
3864 			/* Tx descs/resources not available */
3865 			mutex_enter(&ringp->s_ring_lock);
3866 			if (ringp->s_ring_state & S_RING_ENQUEUED) {
3867 				cookie = mac_tx_sring_enqueue(ringp, mp_chain,
3868 				    flag, ret_mp);
3869 				mutex_exit(&ringp->s_ring_lock);
3870 				return (cookie);
3871 			}
3872 			/*
3873 			 * While we were computing mblk count, the
3874 			 * flow control condition got relieved.
3875 			 * Continue with the transmission.
3876 			 */
3877 			mutex_exit(&ringp->s_ring_lock);
3878 		}
3879 		is_subflow = ((mac_srs->srs_type & SRST_FLOW) != 0);
3880 
3881 		mp_chain = mac_tx_send(ringp->s_ring_tx_arg1,
3882 		    ringp->s_ring_tx_arg2, mp_chain,
3883 		    (is_subflow ? &stats : NULL));
3884 
3885 		/*
3886 		 * Multiple threads could be here sending packets.
3887 		 * Under such conditions, it is not possible to
3888 		 * automically set S_RING_BLOCKED bit to indicate
3889 		 * out of tx desc condition. To atomically set
3890 		 * this, we queue the returned packet and do
3891 		 * the setting of S_RING_BLOCKED in
3892 		 * mac_tx_soft_ring_drain().
3893 		 */
3894 		if (mp_chain != NULL) {
3895 			mutex_enter(&ringp->s_ring_lock);
3896 			cookie =
3897 			    mac_tx_sring_enqueue(ringp, mp_chain, flag, ret_mp);
3898 			mutex_exit(&ringp->s_ring_lock);
3899 			return (cookie);
3900 		}
3901 		if (is_subflow) {
3902 			FLOW_TX_STATS_UPDATE(mac_srs->srs_flent, &stats);
3903 		}
3904 		return (NULL);
3905 	}
3906 }
3907